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7 years agoMerge branches 'cond_resched.2017.12.04a', 'dyntick.2017.11.28a', 'fixes.2017.12...
Paul E. McKenney [Mon, 11 Dec 2017 17:21:58 +0000 (09:21 -0800)]
Merge branches 'cond_resched.2017.12.04a', 'dyntick.2017.11.28a', 'fixes.2017.12.11a', 'srbd.2017.12.05a' and 'torture.2017.12.11a' into HEAD

cond_resched.2017.12.04a: Convert cond_resched_rcu_qs() to cond_resched()
dyntick.2017.11.28a: Make RCU dynticks handle interrupts from NMI
fixes.2017.12.11a: Miscellaneous fixes
srbd.2017.12.05a: Remove now-redundant smp_read_barrier_depends()
torture.2017.12.11a: Torture-testing update

7 years agotorture: Save a line in stutter_wait(): while -> for
Paul E. McKenney [Wed, 22 Nov 2017 06:07:59 +0000 (22:07 -0800)]
torture: Save a line in stutter_wait(): while -> for

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotorture: Eliminate torture_runnable and perf_runnable
Paul E. McKenney [Wed, 22 Nov 2017 04:19:17 +0000 (20:19 -0800)]
torture: Eliminate torture_runnable and perf_runnable

The purpose of torture_runnable is to allow rcutorture and locktorture
to be started and stopped via sysfs when they are built into the kernel
(as in not compiled as loadable modules).  However, the 0444 permissions
for both instances of torture_runnable prevent this use case from ever
being put into practice.  Given that there have been no complaints
about this deficiency, it is reasonable to conclude that no one actually
makes use of this sysfs capability.  The perf_runnable module parameter
for rcuperf is in the same situation.

This commit therefore removes both torture_runnable instances as well
as perf_runnable.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotorture: Make stutter less vulnerable to compilers and races
Paul E. McKenney [Tue, 21 Nov 2017 23:01:02 +0000 (15:01 -0800)]
torture: Make stutter less vulnerable to compilers and races

The stutter_wait() function repeatedly fetched stutter_pause_test, and
should really just fetch it once on each pass.  The races should be
harmless, but why have the races?  Also, the whole point of the value
"2" for stutter_pause_test is to get everyone to start at very nearly
the same time, but the value "2" was the first jiffy of the stutter
rather than the last jiffy of the stutter.

This commit rearranges the code to be more sensible.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agolocking/locktorture: Fix num reader/writer corner cases
Davidlohr Bueso [Mon, 15 May 2017 09:07:23 +0000 (02:07 -0700)]
locking/locktorture: Fix num reader/writer corner cases

Things can explode for locktorture if the user does combinations
of nwriters_stress=0 nreaders_stress=0. Fix this by not assuming
we always want to torture writer threads.

Reported-by: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
7 years agolocking/locktorture: Fix rwsem reader_delay
Davidlohr Bueso [Mon, 15 May 2017 09:07:22 +0000 (02:07 -0700)]
locking/locktorture: Fix rwsem reader_delay

We should account for nreader threads, not writers in this
callback. Could even trigger a div by 0 if the user explicitly
disables writers.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotorture: Place all torture-test modules in one MAINTAINERS group
Paul E. McKenney [Tue, 7 Nov 2017 22:10:03 +0000 (14:10 -0800)]
torture: Place all torture-test modules in one MAINTAINERS group

There is some confusion about where patches to kernel/torture.c
and kernel/locking/locktorture.c should be sent.  This commit
therefore updates MAINTAINERS appropriately.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
7 years agorcutorture/kvm-build.sh: Skip build directory check
SeongJae Park [Fri, 3 Nov 2017 10:17:26 +0000 (19:17 +0900)]
rcutorture/kvm-build.sh: Skip build directory check

Check for build-directory existence and write permissions are provided in
both 'kvm-test-1-run.sh' an 'kvm-build.sh'.  Because the 'kvm-build.sh'
is dependent on 'kvm-test-1-run.sh' ('kvm-build.sh' uses variables that
defined from its caller.), these checks are unnecessarily duplicated.
This commit therefore removes the check in from the 'kvm-build.sh' script.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture: Simplify functions.sh include path
SeongJae Park [Fri, 3 Nov 2017 10:17:28 +0000 (19:17 +0900)]
rcutorture: Simplify functions.sh include path

Inclusions of 'functions.sh' from 'kvm-test-1-run.sh' and
'kvm-recheck*.sh' use its absolute path.  Because the directory containing
'functions.sh' is already in PATH, the full path is unnecessary.  This
commit therefore simplifies the inclusions to use the short relative path.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture: Simplify logging
SeongJae Park [Fri, 3 Nov 2017 10:17:27 +0000 (19:17 +0900)]
rcutorture: Simplify logging

Both the 'kvm.sh' and 'kvm-test-1-run.sh' scripts log messages by printing
the message to 'stdout' and then also printing it into the log file.
Generation of the message thus occurs twice, once for 'stdout' and once
for the log file.  Moreover, many of the messages contain 'date' output,
which results in date being invoked twice (once for stdout print, once
for log file write).  As a result, the date information in stdout and
log file can differ, which could cause confusion.

This commit therefore simplifies the logging procedure by using 'tee'.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture/kvm-recheck-*: Improve result directory readability check
SeongJae Park [Fri, 3 Nov 2017 10:17:25 +0000 (19:17 +0900)]
rcutorture/kvm-recheck-*: Improve result directory readability check

The kvm-recheck-(lock|rcu|rcuperf).sh scripts check whether the
user-specified results directory exists.  If not, it prints out error
message that says the specified directory is unreadable.  To make the
message more precise, this commit adds a readability check.

Fixes: 2193e1604eac ("rcutorture: Abstract kvm-recheck.sh")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture/kvm.sh: Support execution from any directory
SeongJae Park [Fri, 3 Nov 2017 10:17:24 +0000 (19:17 +0900)]
rcutorture/kvm.sh: Support execution from any directory

The 'kvm.sh' rcutorture script requires that it be invoked from the top
of Linux-kernel source tree.  It is just a subtle restriction, but users
using it for the first time could forget the restriction and be confused.
Moreover, it makes commands a little longer, which can be frustrating.
This commit therefore lets users invoke the script from any location.

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture/kvm.sh: Use consistent help text for --qemu-args
SeongJae Park [Fri, 3 Nov 2017 10:17:23 +0000 (19:17 +0900)]
rcutorture/kvm.sh: Use consistent help text for --qemu-args

The '--qemu-args' option's help text is wrongly copied from '--qemu-cmd'
option and its argument type description message format is inconsistent
with other arguments.  This commit fixes the usage and type messages to
be consistent with others.

Fixes: e9ce640001c6 ("rcutorture: Add --qemu-args argument to kvm.sh")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture/kvm.sh: Remove unused variable, `alldone`
SeongJae Park [Fri, 3 Nov 2017 10:17:22 +0000 (19:17 +0900)]
rcutorture/kvm.sh: Remove unused variable, `alldone`

The variable `alldone` is defined but not used within an awk script.
This commit therefore removes it.

Fixes:53954671033d ("rcutorture: Do better bin packing")

Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture: Remove unused script, config2frag.sh
SeongJae Park [Fri, 3 Nov 2017 10:17:21 +0000 (19:17 +0900)]
rcutorture: Remove unused script, config2frag.sh

The 'config2frag.sh' script is not used, so this commit removes it.

Fixes: c87b9c601ac8 ("rcutorture: Add KVM-based test framework")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture/configinit: Fix build directory error message
SeongJae Park [Fri, 3 Nov 2017 10:17:20 +0000 (19:17 +0900)]
rcutorture/configinit: Fix build directory error message

The 'configinit.sh' script checks the format of optional argument for the
build directory, printing an error message if the format is not valid.
However, the error message uses the wrong variable, indicating an empty
string even though the user entered a non-empty (but erroneous) string.
This commit fixes the script to use the correct variable.

Fixes: c87b9c601ac8 ("rcutorture: Add KVM-based test framework")
Signed-off-by: SeongJae Park <sj38.park@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcutorture: Preempt RCU-preempt readers more vigorously
Paul E. McKenney [Mon, 16 Oct 2017 18:23:42 +0000 (11:23 -0700)]
rcutorture: Preempt RCU-preempt readers more vigorously

This commit attempts to make a very rare rcutorture failure happen
more often by increasing the fraction of RCU-preempt read-side critical
sections that are preempted.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotorture: Reduce #ifdefs for preempt_schedule()
Paul E. McKenney [Mon, 16 Oct 2017 18:05:03 +0000 (11:05 -0700)]
torture: Reduce #ifdefs for preempt_schedule()

This commit adds a torture_preempt_schedule() that is nothingness
in !PREEMPT builds and is preempt_schedule() otherwise.  Then
torture_preempt_schedule() is used to eliminate several ugly #ifdefs,
both in rcutorture and in locktorture.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Remove have_rcu_nocb_mask from tree_plugin.h
Rakib Mullick [Fri, 17 Nov 2017 15:40:15 +0000 (21:40 +0600)]
rcu: Remove have_rcu_nocb_mask from tree_plugin.h

Currently have_rcu_nocb_mask is used to avoid double allocation of
rcu_nocb_mask during boot up. Due to different representation of
cpumask_var_t on different kernel config CPUMASK=y(or n) it was okay.
But now we have a helper cpumask_available(), which can be utilized
to check whether rcu_nocb_mask has been allocated or not without using
a variable.

Removing the variable also reduces vmlinux size.

Unpatched version:
text    data     bss     dec     hex filename
13050393 7852470 14543408 35446271 21cddff vmlinux

Patched version:
 text    data     bss     dec     hex filename
13050390 7852438 14543408 35446236 21cdddc vmlinux

Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Add comment giving debug strategy for double call_rcu()
Paul E. McKenney [Thu, 19 Oct 2017 21:52:41 +0000 (14:52 -0700)]
rcu: Add comment giving debug strategy for double call_rcu()

The following statement has for some reason proven non-intuitive:

WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != (count == 0));

This commit therefore adds a comment that states that this warning
usually triggers in response to a double call_rcu(), which is sort
of like a double free.  The comment also suggests building with
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y to track down the double call_rcu().

Reported-by: David Howells <dhowells@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotracing, rcu: Hide trace event rcu_nocb_wake when not used
Steven Rostedt (VMware) [Thu, 12 Oct 2017 22:16:41 +0000 (18:16 -0400)]
tracing, rcu: Hide trace event rcu_nocb_wake when not used

The trace event rcu_nocb_wake is only used when CONFIG_RCU_NOCB_CPU is
defined. But the trace event is defined regardless. As defined trace
events take up memory, it is a waste to have it defined when not used.
Surround the trace event with an #ifdef to have it only defined when it
is used.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agodrivers/vhost: Remove now-redundant read_barrier_depends()
Paul E. McKenney [Mon, 27 Nov 2017 17:45:10 +0000 (09:45 -0800)]
drivers/vhost: Remove now-redundant read_barrier_depends()

Because READ_ONCE() now implies read_barrier_depends(), the
read_barrier_depends() in next_desc() is now redundant.  This commit
therefore removes it and the related comments.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: <kvm@vger.kernel.org>
Cc: <virtualization@lists.linux-foundation.org>
Cc: <netdev@vger.kernel.org>
7 years agocheckpatch: Add warnings for {smp_,}read_barrier_depends()
Paul E. McKenney [Mon, 27 Nov 2017 17:37:35 +0000 (09:37 -0800)]
checkpatch: Add warnings for {smp_,}read_barrier_depends()

Now that both smp_read_barrier_depends() and read_barrier_depends()
are being de-emphasized, warn if any are added.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
[ paulmck: Skipped checking files and handled whitespace per Joe Perches. ]

7 years agonetlink: Remove smp_read_barrier_depends() from comment
Paul E. McKenney [Mon, 27 Nov 2017 17:26:06 +0000 (09:26 -0800)]
netlink: Remove smp_read_barrier_depends() from comment

Now that smp_read_barrier_depends() has been de-emphasized, the less
said about it, the better.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Cc: <netfilter-devel@vger.kernel.org>
Cc: <coreteam@netfilter.org>
7 years agogenetlink: Remove smp_read_barrier_depends() from comment
Paul E. McKenney [Mon, 27 Nov 2017 17:23:24 +0000 (09:23 -0800)]
genetlink: Remove smp_read_barrier_depends() from comment

Now that smp_read_barrier_depends() has been de-emphasized, the less
said about it, the better.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
7 years agodoc: De-emphasize smp_read_barrier_depends
Paul E. McKenney [Mon, 27 Nov 2017 17:20:40 +0000 (09:20 -0800)]
doc: De-emphasize smp_read_barrier_depends

This commit keeps only the historical and low-level discussion of
smp_read_barrier_depends().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Adjusted to allow for David Howells feedback on prior commit. ]

7 years agodrivers/dma/ioat: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Sat, 2 Dec 2017 01:04:39 +0000 (17:04 -0800)]
drivers/dma/ioat: Remove now-redundant smp_read_barrier_depends()

Now that READ_ONCE() implies smp_read_barrier_depends(), the
__cleanup() and ioat_abort_descs() functions no longer need their
smp_read_barrier_depends() calls, which this commit removes.
It is actually not entirely clear why this driver ever included
smp_read_barrier_depends() given that it appears to be x86-only and
given that smp_read_barrier_depends() has no effect whatsoever except
on DEC Alpha.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <dmaengine@vger.kernel.org>
7 years agodrivers/infiniband: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 27 Nov 2017 17:04:22 +0000 (09:04 -0800)]
drivers/infiniband: Remove now-redundant smp_read_barrier_depends()

The smp_read_barrier_depends() does nothing at all except on DEC Alpha,
and no current DEC Alpha systems use Infiniband:

lkml.kernel.org/r/20171023085921.jwbntptn6ictbnvj@tower

This commit therefore makes Infiniband depend on !ALPHA and removes
the now-ineffective invocations of smp_read_barrier_depends() from
the InfiniBand driver.

Please note that this patch should not be construed as my saying that
InfiniBand's memory ordering is correct, but rather that this patch does
not in any way affect InfiniBand's correctness.  In other words, the
result of applying this patch is bug-for-bug compatible with the original.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Doug Ledford <dledford@redhat.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Cree <mcree@orcon.net.nz>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: <linux-rdma@vger.kernel.org>
Cc: <linux-alpha@vger.kernel.org>
[ paulmck: Removed drivers/dma/ioat/dma.c per Jason Gunthorpe's feedback. ]
Acked-by: Jason Gunthorpe <jgg@mellanox.com>
7 years agokeyring: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 19:19:27 +0000 (12:19 -0700)]
keyring: Remove now-redundant smp_read_barrier_depends()

Now that the associative-array library properly heads dependency chains,
the various smp_read_barrier_depends() calls in security/keys/keyring.c
are no longer needed.  This commit therefore removes them.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: <keyrings@vger.kernel.org>
Cc: <linux-security-module@vger.kernel.org>
Reviewed-by: James Morris <james.l.morris@oracle.com>
7 years agonetfilter: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 19:09:04 +0000 (12:09 -0700)]
netfilter: Remove now-redundant smp_read_barrier_depends()

READ_ONCE() now implies smp_read_barrier_depends(), which means that
the instances in arpt_do_table(), ipt_do_table(), and ip6t_do_table()
are now redundant.  This commit removes them and adjusts the comments.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netfilter-devel@vger.kernel.org>
Cc: <coreteam@netfilter.org>
Cc: <netdev@vger.kernel.org>
7 years agomm/ksm: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 18:51:45 +0000 (11:51 -0700)]
mm/ksm: Remove now-redundant smp_read_barrier_depends()

Because READ_ONCE() now implies smp_read_barrier_depends(), the
smp_read_barrier_depends() in get_ksm_page() is now redundant.
This commit removes it and updates the comments.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: <linux-mm@kvack.org>
7 years agolib/assoc_array: Remove smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 18:39:57 +0000 (11:39 -0700)]
lib/assoc_array: Remove smp_read_barrier_depends()

Now that smp_read_barrier_depends() is implied by READ_ONCE(), the several
smp_read_barrier_depends() calls may be removed from lib/assoc_array.c.
This commit makes this change and marks the READ_ONCE() calls that head
address dependencies.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Kuleshov <kuleshovmail@gmail.com>
Cc: David Howells <dhowells@redhat.com>
7 years agotracepoint: Remove smp_read_barrier_depends() from comment
Paul E. McKenney [Mon, 9 Oct 2017 18:30:11 +0000 (11:30 -0700)]
tracepoint: Remove smp_read_barrier_depends() from comment

The comment in tracepoint_add_func() mentions smp_read_barrier_depends(),
whose use should be quite restricted.  This commit updates the comment
to instead mention the smp_store_release() and rcu_dereference_sched()
that the current code actually uses.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 years agolocking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath()
Paul E. McKenney [Mon, 9 Oct 2017 18:22:50 +0000 (11:22 -0700)]
locking: Remove smp_read_barrier_depends() from queued_spin_lock_slowpath()

Queued spinlocks are not used by DEC Alpha, and furthermore operations
such as READ_ONCE() and release/relaxed RMW atomics are being changed
to imply smp_read_barrier_depends().  This commit therefore removes the
now-redundant smp_read_barrier_depends() from queued_spin_lock_slowpath(),
and adjusts the comments accordingly.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
7 years agouprobes: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 18:08:53 +0000 (11:08 -0700)]
uprobes: Remove now-redundant smp_read_barrier_depends()

Now that READ_ONCE() implies smp_read_barrier_depends(), the
get_xol_area() and get_trampoline_vaddr() no longer need their
smp_read_barrier_depends() calls, which this commit removes.
While we are here, convert the corresponding smp_wmb() to an
smp_store_release().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
7 years agoseqlock: Remove now-redundant smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 18:00:32 +0000 (11:00 -0700)]
seqlock: Remove now-redundant smp_read_barrier_depends()

READ_ONCE() now implies smp_read_barrier_depends(), so this patch
removes the now-redundant smp_read_barrier_depends() from
raw_read_seqcount_latch().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
7 years agortnetlink: Update now-misleading smp_read_barrier_depends() comment
Paul E. McKenney [Mon, 9 Oct 2017 17:37:22 +0000 (10:37 -0700)]
rtnetlink: Update now-misleading smp_read_barrier_depends() comment

Now that READ_ONCE() implies smp_read_barrier_depends(), update the
rtnl_dereference() header comment accordingly.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Vladislav Yasevich <vyasevic@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
7 years agorcu: Adjust read-side accessor comments for READ_ONCE()
Paul E. McKenney [Mon, 9 Oct 2017 17:30:58 +0000 (10:30 -0700)]
rcu: Adjust read-side accessor comments for READ_ONCE()

Now that READ_ONCE() implies smp_read_barrier_depends(), the commit
updates now-misleading comments to account for this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agopercpu: READ_ONCE() now implies smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 17:20:44 +0000 (10:20 -0700)]
percpu: READ_ONCE() now implies smp_read_barrier_depends()

Because READ_ONCE() now implies smp_read_barrier_depends(), this commit
removes the now-redundant smp_read_barrier_depends() following the
READ_ONCE() in __ref_is_percpu().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
7 years agofs/dcache: Use release-acquire for name/length update
Paul E. McKenney [Mon, 9 Oct 2017 17:04:27 +0000 (10:04 -0700)]
fs/dcache: Use release-acquire for name/length update

The code in __d_alloc() carefully orders filling in the NUL character
of the name (and the length, hash, and the name itself) with assigning
of the name itself.  However, prepend_name() does not order the accesses
to the ->name and ->len fields, other than on TSO systems.  This commit
therefore replaces prepend_name()'s READ_ONCE() of ->name with an
smp_load_acquire(), which orders against the subsequent READ_ONCE() of
->len.  Because READ_ONCE() now incorporates smp_read_barrier_depends(),
prepend_name()'s smp_read_barrier_depends() is removed.  Finally,
to save a line, the smp_wmb()/store pair in __d_alloc() is replaced
by smp_store_release().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
7 years agodrivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering
Paul E. McKenney [Mon, 9 Oct 2017 16:26:25 +0000 (09:26 -0700)]
drivers/net/ethernet/qlogic/qed: Fix __qed_spq_block() ordering

The __qed_spq_block() function expects an smp_read_barrier_depends()
to order a prior READ_ONCE() against a later load that does not depend
on the prior READ_ONCE(), an expectation that can fail to be met.
This commit therefore replaces the READ_ONCE() with smp_load_acquire()
and removes the smp_read_barrier_depends().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ariel Elior <Ariel.Elior@cavium.com>
Cc: <everest-linux-l2@cavium.com>
Cc: <netdev@vger.kernel.org>
7 years agomn10300: READ_ONCE() now implies smp_read_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 16:17:49 +0000 (09:17 -0700)]
mn10300: READ_ONCE() now implies smp_read_barrier_depends()

Given that READ_ONCE() now implies smp_read_barrier_depends(),
there is no need for the open-coded smp_read_barrier_depends() in
mn10300_serial_receive_interrupt() and mn10300_serial_poll_get_char().
This commit therefore removes them, but replaces them with comments
calling out that carrying dependencies through non-pointers is quite
dangerous.  Compilers simply know too much about integers.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: <linux-am33-list@redhat.com>
7 years agodoc: READ_ONCE() now implies smp_barrier_depends()
Paul E. McKenney [Mon, 9 Oct 2017 16:15:21 +0000 (09:15 -0700)]
doc: READ_ONCE() now implies smp_barrier_depends()

This commit updates an example in memory-barriers.txt to account for
the fact that READ_ONCE() now implies smp_barrier_depends().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Added MEMORY_BARRIER instructions from DEC Alpha from
  READ_ONCE(), per David Howells's feedback. ]

7 years agorcu: Account for rcu_all_qs() in cond_resched()
Paul E. McKenney [Sun, 5 Nov 2017 13:51:43 +0000 (05:51 -0800)]
rcu: Account for rcu_all_qs() in cond_resched()

If cond_resched() returns false, then it has already invoked
rcu_all_qs().  This is also invoked (now redundantly) by
rcu_note_voluntary_context_switch().  This commit therefore changes
cond_resched_rcu_qs() to invoke rcu_note_voluntary_context_switch_lite()
instead of rcu_note_voluntary_context_switch() to avoid the redundant
invocation of rcu_all_qs().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agodoc: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:42:41 +0000 (08:42 -0700)]
doc: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore documents this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agofs: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:39:34 +0000 (08:39 -0700)]
fs: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
7 years agosoftirq: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:31:12 +0000 (08:31 -0700)]
softirq: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: NeilBrown <neilb@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
7 years agotrace: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:26:32 +0000 (08:26 -0700)]
trace: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
7 years agoworkqueue: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:25:02 +0000 (08:25 -0700)]
workqueue: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
7 years agomm: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 15:22:18 +0000 (08:22 -0700)]
mm: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
7 years agonetfilter: Eliminate cond_resched_rcu_qs() in favor of cond_resched()
Paul E. McKenney [Tue, 24 Oct 2017 13:48:39 +0000 (06:48 -0700)]
netfilter: Eliminate cond_resched_rcu_qs() in favor of cond_resched()

Now that cond_resched() also provides RCU quiescent states when
needed, it can be used in place of cond_resched_rcu_qs().  This
commit therefore makes this change.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Florian Westphal <fw@strlen.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <netfilter-devel@vger.kernel.org>
7 years agosched: Stop switched_to_rt() from sending IPIs to offline CPUs
Paul E. McKenney [Sat, 14 Oct 2017 00:00:18 +0000 (17:00 -0700)]
sched: Stop switched_to_rt() from sending IPIs to offline CPUs

The rcutorture test suite occasionally provokes a splat due to invoking
rt_mutex_lock() which needs to boost the priority of a task currently
sitting on a runqueue that belongs to an offline CPU:

WARNING: CPU: 0 PID: 12 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 0 PID: 12 Comm: rcub/7 Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff9ed3de5f8cc0 task.stack: ffffbbf80012c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffffbbf80012fd10 EFLAGS: 00010082
RAX: 000000000000002f RBX: ffff9ed3dd9cb300 RCX: 0000000000000004
RDX: 0000000080000004 RSI: 0000000000000086 RDI: 00000000ffffffff
RBP: ffffbbf80012fd10 R08: 000000000009da7a R09: 0000000000007b9d
R10: 0000000000000001 R11: ffffffffbb57c2cd R12: 000000000000000d
R13: ffff9ed3de5f8cc0 R14: 0000000000000061 R15: ffff9ed3ded59200
FS:  0000000000000000(0000) GS:ffff9ed3dea00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000080686f0 CR3: 000000001b9e0000 CR4: 00000000000006f0
Call Trace:
 resched_curr+0x61/0xd0
 switched_to_rt+0x8f/0xa0
 rt_mutex_setprio+0x25c/0x410
 task_blocks_on_rt_mutex+0x1b3/0x1f0
 rt_mutex_slowlock+0xa9/0x1e0
 rt_mutex_lock+0x29/0x30
 rcu_boost_kthread+0x127/0x3c0
 kthread+0x104/0x140
 ? rcu_report_unblock_qs_rnp+0x90/0x90
 ? kthread_create_on_node+0x40/0x40
 ret_from_fork+0x22/0x30
Code: f0 00 0f 92 c0 84 c0 74 14 48 8b 05 34 74 c5 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 a0 c6 fc b9 e8 d5 b5 06 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 a2 d1 13 02 85 c0 75 38 55 48

But the target task's priority has already been adjusted, so the only
purpose of switched_to_rt() invoking resched_curr() is to wake up the
CPU running some task that needs to be preempted by the boosted task.
But the CPU is offline, which presumably means that the task must be
migrated to some other CPU, and that this other CPU will undertake any
needed preemption at the time of migration.  Because the runqueue lock
is held when resched_curr() is invoked, we know that the boosted task
cannot go anywhere, so it is not necessary to invoke resched_curr()
in this particular case.

This commit therefore makes switched_to_rt() refrain from invoking
resched_curr() when the target CPU is offline.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
7 years agosched: Stop resched_cpu() from sending IPIs to offline CPUs
Paul E. McKenney [Fri, 13 Oct 2017 23:24:28 +0000 (16:24 -0700)]
sched: Stop resched_cpu() from sending IPIs to offline CPUs

The rcutorture test suite occasionally provokes a splat due to invoking
resched_cpu() on an offline CPU:

WARNING: CPU: 2 PID: 8 at /home/paulmck/public_git/linux-rcu/arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x37/0x40
Modules linked in:
CPU: 2 PID: 8 Comm: rcu_preempt Not tainted 4.14.0-rc4+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
task: ffff902ede9daf00 task.stack: ffff96c50010c000
RIP: 0010:native_smp_send_reschedule+0x37/0x40
RSP: 0018:ffff96c50010fdb8 EFLAGS: 00010096
RAX: 000000000000002e RBX: ffff902edaab4680 RCX: 0000000000000003
RDX: 0000000080000003 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: ffff96c50010fdb8 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 00000000299f36ae R12: 0000000000000001
R13: ffffffff9de64240 R14: 0000000000000001 R15: ffffffff9de64240
FS:  0000000000000000(0000) GS:ffff902edfc80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f7d4c642 CR3: 000000001e0e2000 CR4: 00000000000006e0
Call Trace:
 resched_curr+0x8f/0x1c0
 resched_cpu+0x2c/0x40
 rcu_implicit_dynticks_qs+0x152/0x220
 force_qs_rnp+0x147/0x1d0
 ? sync_rcu_exp_select_cpus+0x450/0x450
 rcu_gp_kthread+0x5a9/0x950
 kthread+0x142/0x180
 ? force_qs_rnp+0x1d0/0x1d0
 ? kthread_create_on_node+0x40/0x40
 ret_from_fork+0x27/0x40
Code: 14 01 0f 92 c0 84 c0 74 14 48 8b 05 14 4f f4 00 be fd 00 00 00 ff 90 a0 00 00 00 5d c3 89 fe 48 c7 c7 38 89 ca 9d e8 e5 56 08 00 <0f> ff 5d c3 0f 1f 44 00 00 8b 05 52 9e 37 02 85 c0 75 38 55 48
---[ end trace 26df9e5df4bba4ac ]---

This splat cannot be generated by expedited grace periods because they
always invoke resched_cpu() on the current CPU, which is good because
expedited grace periods require that resched_cpu() unconditionally
succeed.  However, other parts of RCU can tolerate resched_cpu() acting
as a no-op, at least as long as it doesn't happen too often.

This commit therefore makes resched_cpu() invoke resched_curr() only if
the CPU is either online or is the current CPU.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
7 years agotorture: Prepare scripting for shift from %p to %pK
Paul E. McKenney [Thu, 12 Oct 2017 18:00:33 +0000 (11:00 -0700)]
torture: Prepare scripting for shift from %p to %pK

Because %p prints "(null)" and %pK prints "0000000000000000" or (on
32-bit systems) "00000000", this commit adjusts torture-test scripting
accordingly.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotorture: Suppress CPU stall warnings during shutdown ftrace dump
Paul E. McKenney [Wed, 4 Oct 2017 18:23:10 +0000 (11:23 -0700)]
torture: Suppress CPU stall warnings during shutdown ftrace dump

The torture_shutdown() function directly invokes ftrace_dump(), which
can result in RCU CPU stall warnings when the ftrace buffer is large,
which it usually is.  This commit therefore invoks rcu_ftrace_dump()
in place of ftrace_dump(), suppressing RCU CPU stall warnings during
this time.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agosrcu: Prohibit call_srcu() use under raw spinlocks
Paul E. McKenney [Tue, 10 Oct 2017 20:52:30 +0000 (13:52 -0700)]
srcu: Prohibit call_srcu() use under raw spinlocks

Invoking queue_delayed_work() while holding a raw spinlock is forbidden
in -rt kernels, which is exactly what __call_srcu() does, indirectly via
srcu_funnel_gp_start().  This commit therefore downgrades Tree SRCU's
locking from raw to non-raw spinlocks, which works because call_srcu()
is not ever called while holding a raw spinlock.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agotracing, rcu: Remove no longer used trace event rcu_prep_idle
Steven Rostedt (VMware) [Thu, 12 Oct 2017 22:12:57 +0000 (18:12 -0400)]
tracing, rcu: Remove no longer used trace event rcu_prep_idle

Commit c0f4dfd4f90 ("rcu: Make RCU_FAST_NO_HZ take advantage of
numbered callbacks") removed the only instances of trace_rcu_prep_idle,
but did not remove the TRACE_EVENT() that creates it. As defined trace
events take up memory within the kernel even when they are not used,
this is a waste of space. Remove the obsolete event.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agodoc: Update dyntick-idle design documentation for NMI/irq consolidation
Paul E. McKenney [Fri, 6 Oct 2017 20:48:14 +0000 (13:48 -0700)]
doc: Update dyntick-idle design documentation for NMI/irq consolidation

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Simplify rcu_eqs_{enter,exit}() non-idle task debug code
Paul E. McKenney [Fri, 6 Oct 2017 02:55:31 +0000 (19:55 -0700)]
rcu: Simplify rcu_eqs_{enter,exit}() non-idle task debug code

The code that checks for non-idle non-nohz_idle-usermode tasks invoking
rcu_eqs_enter() and rcu_eqs_exit() prints a considerable quantity of
helpful information.  However, these checks fire rarely, so the extra
complexity is no longer worth it.  This commit therefore replaces this
debug code with simple WARN_ON_ONCE() statements.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Fold rcu_eqs_exit_common() into rcu_eqs_exit()
Paul E. McKenney [Thu, 5 Oct 2017 23:56:26 +0000 (16:56 -0700)]
rcu: Fold rcu_eqs_exit_common() into rcu_eqs_exit()

There is now only one call to rcu_eqs_exit_common() and there is no other
reason to keep it separate.  This commit therefore inlines it into its
sole call site, saving a few lines of code in the process.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Fold rcu_eqs_enter_common() into rcu_eqs_enter()
Paul E. McKenney [Thu, 5 Oct 2017 23:37:03 +0000 (16:37 -0700)]
rcu: Fold rcu_eqs_enter_common() into rcu_eqs_enter()

There is now only one call to rcu_eqs_enter_common() and there is no other
reason to keep it separate.  This commit therefore inlines it into its
sole call site, saving a few lines of code in the process.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Avoid ->dynticks_nesting store tearing
Paul E. McKenney [Thu, 5 Oct 2017 22:03:10 +0000 (15:03 -0700)]
rcu: Avoid ->dynticks_nesting store tearing

Although ->dynticks_nesting is updated only by process level, it is
accessed from hardirq to check for interrupt-from-idle quiescent states.
Store tearing is thus possible, so this commit applies WRITE_ONCE()
to ->dynticks_nesting stores.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Stop duplicating lockdep checks in RCU's idle-entry code
Paul E. McKenney [Thu, 5 Oct 2017 20:50:57 +0000 (13:50 -0700)]
rcu: Stop duplicating lockdep checks in RCU's idle-entry code

The three RCU_LOCKDEP_WARN() calls in rcu_eqs_enter_common() are
redundant with other lockdep checks, so this commit removes them.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Add ->dynticks field to rcu_dyntick trace event
Paul E. McKenney [Wed, 4 Oct 2017 23:24:29 +0000 (16:24 -0700)]
rcu: Add ->dynticks field to rcu_dyntick trace event

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Shrink ->dynticks_{nmi_,}nesting from long long to long
Paul E. McKenney [Wed, 4 Oct 2017 22:55:16 +0000 (15:55 -0700)]
rcu: Shrink ->dynticks_{nmi_,}nesting from long long to long

Because the ->dynticks_nesting field now only contains the process-based
nesting level instead of a value encoding both the process nesting level
and the irq "nesting" level, we no longer need a long long, even on
32-bit systems.  This commit therefore changes both the ->dynticks_nesting
and ->dynticks_nmi_nesting fields to long.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Add tracing to irq/NMI dyntick-idle transitions
Paul E. McKenney [Wed, 4 Oct 2017 19:29:01 +0000 (12:29 -0700)]
rcu: Add tracing to irq/NMI dyntick-idle transitions

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Eliminate rcu_irq_enter_disabled()
Paul E. McKenney [Tue, 3 Oct 2017 23:51:47 +0000 (16:51 -0700)]
rcu: Eliminate rcu_irq_enter_disabled()

Now that the irq path uses the rcu_nmi_{enter,exit}() algorithm,
rcu_irq_enter() and rcu_irq_exit() may be used from any context.  There is
thus no need for rcu_irq_enter_disabled() and for the checks using it.
This commit therefore eliminates rcu_irq_enter_disabled().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Make ->dynticks_nesting be a simple counter
Paul E. McKenney [Tue, 3 Oct 2017 21:43:40 +0000 (14:43 -0700)]
rcu: Make ->dynticks_nesting be a simple counter

Now that ->dynticks_nesting counts only process-level dyntick-idle
entry and exit, there is no need for the elaborate segmented counter
with its guard fields and overflow checking.  This commit therefore
makes ->dynticks_nesting be a simple counter.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Define rcu_irq_{enter,exit}() in terms of rcu_nmi_{enter,exit}()
Paul E. McKenney [Tue, 3 Oct 2017 17:42:22 +0000 (10:42 -0700)]
rcu: Define rcu_irq_{enter,exit}() in terms of rcu_nmi_{enter,exit}()

RCU currently uses two different mechanisms for tracking irqs and NMIs.
This is unnecessary complexity: Given that NMIs can nest and given that
RCU's tracking handles such nesting, the NMI tracking mechanism can also
be used to track irqs.  This commit therefore defines rcu_irq_enter()
in terms of rcu_nmi_enter() and rcu_irq_exit() in terms of rcu_nmi_exit().

Unfortunately, callers must still distinguish between the irq and NMI
functions because additional actions are taken when an irq interrupts
idle or nohz_full usermode execution, and these actions cannot always
be taken from NMI handlers.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Clamp ->dynticks_nmi_nesting at eqs entry/exit
Paul E. McKenney [Tue, 3 Oct 2017 15:28:04 +0000 (08:28 -0700)]
rcu: Clamp ->dynticks_nmi_nesting at eqs entry/exit

In preparation for merging dyntick-idle irq handling into the NMI
algorithm, clamp ->dynticks_nmi_nesting value to allow for interrupts
that enter but never leave and vice versa.

It is important that the clamping happen outside of the extended quiescent
state.  Otherwise, there will be short windows where irqs and NMIs fail
to convince RCU to start watching.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Move rcu_nmi_{enter,exit}() to prepare for consolidation
Paul E. McKenney [Tue, 3 Oct 2017 04:56:20 +0000 (21:56 -0700)]
rcu: Move rcu_nmi_{enter,exit}() to prepare for consolidation

This is a code-motion-only commit that prepares to define rcu_irq_enter()
in terms of rcu_nmi_enter() and rcu_irq_exit() in terms of rcu_irq_exit().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Reduce dyntick-idle state space
Paul E. McKenney [Tue, 3 Oct 2017 02:45:10 +0000 (19:45 -0700)]
rcu: Reduce dyntick-idle state space

Both extended-quiescent-state entry and exit first update the nesting
counter and then adjust the dyntick-idle state.  This means that there
are four states: (1) Both nesting and dyntick idle indicate idle,
(2) Nesting indicates idle but dyntick idle does not, (3) Nesting indicates
non-idle and dyntick idle does not, and (4) Both nesting and dyntick
idle indicate non-idle.  This commit simplifies the state space by
eliminating #3, reversing the order of updates on exit from extended
quiescent state.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agorcu: Avoid ->dynticks_nmi_nesting store tearing
Paul E. McKenney [Mon, 2 Oct 2017 23:54:49 +0000 (16:54 -0700)]
rcu: Avoid ->dynticks_nmi_nesting store tearing

NMIs can nest, and store tearing could in theory happen on carries
from one byte to the next.  This commit therefore adds the WRITE_ONCE()
macros preventing this.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
7 years agoLinux 4.15-rc1 v4.15-rc1
Linus Torvalds [Mon, 27 Nov 2017 00:01:47 +0000 (16:01 -0800)]
Linux 4.15-rc1

7 years agoMerge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm
Linus Torvalds [Sun, 26 Nov 2017 23:03:49 +0000 (15:03 -0800)]
Merge branch 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM fixes from Russell King:

 - LPAE fixes for kernel-readonly regions

 - Fix for get_user_pages_fast on LPAE systems

 - avoid tying decompressor to a particular platform if DEBUG_LL is
   enabled

 - BUG if we attempt to return to userspace but the to-be-restored PSR
   value keeps us in privileged mode (defeating an issue that ftracetest
   found)

* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: BUG if jumping to usermode address in kernel mode
  ARM: 8722/1: mm: make STRICT_KERNEL_RWX effective for LPAE
  ARM: 8721/1: mm: dump: check hardware RO bit for LPAE
  ARM: make decompressor debug output user selectable
  ARM: fix get_user_pages_fast

7 years agoMerge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 22:39:20 +0000 (14:39 -0800)]
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull irq fixes from Thomas Glexiner:

 - unbreak the irq trigger type check for legacy platforms

 - a handful fixes for ARM GIC v3/4 interrupt controllers

 - a few trivial fixes all over the place

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  genirq/matrix: Make - vs ?: Precedence explicit
  irqchip/imgpdc: Use resource_size function on resource object
  irqchip/qcom: Fix u32 comparison with value less than zero
  irqchip/exiu: Fix return value check in exiu_init()
  irqchip/gic-v3-its: Remove artificial dependency on PCI
  irqchip/gic-v4: Add forward definition of struct irq_domain_ops
  irqchip/gic-v3: pr_err() strings should end with newlines
  irqchip/s3c24xx: pr_err() strings should end with newlines
  irqchip/gic-v3: Fix ppi-partitions lookup
  irqchip/gic-v4: Clear IRQ_DISABLE_UNLAZY again if mapping fails
  genirq: Track whether the trigger type has been set

7 years agoMerge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 22:11:54 +0000 (14:11 -0800)]
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 fixes from Ingo Molnar:
 - topology enumeration fixes
 - KASAN fix
 - two entry fixes (not yet the big series related to KASLR)
 - remove obsolete code
 - instruction decoder fix
 - better /dev/mem sanity checks, hopefully working better this time
 - pkeys fixes
 - two ACPI fixes
 - 5-level paging related fixes
 - UMIP fixes that should make application visible faults more debuggable
 - boot fix for weird virtualization environment

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/decoder: Add new TEST instruction pattern
  x86/PCI: Remove unused HyperTransport interrupt support
  x86/umip: Fix insn_get_code_seg_params()'s return value
  x86/boot/KASLR: Remove unused variable
  x86/entry/64: Add missing irqflags tracing to native_load_gs_index()
  x86/mm/kasan: Don't use vmemmap_populate() to initialize shadow
  x86/entry/64: Fix entry_SYSCALL_64_after_hwframe() IRQ tracing
  x86/pkeys/selftests: Fix protection keys write() warning
  x86/pkeys/selftests: Rename 'si_pkey' to 'siginfo_pkey'
  x86/mpx/selftests: Fix up weird arrays
  x86/pkeys: Update documentation about availability
  x86/umip: Print a warning into the syslog if UMIP-protected instructions are used
  x86/smpboot: Fix __max_logical_packages estimate
  x86/topology: Avoid wasting 128k for package id array
  perf/x86/intel/uncore: Cache logical pkg id in uncore driver
  x86/acpi: Reduce code duplication in mp_override_legacy_irq()
  x86/acpi: Handle SCI interrupts above legacy space gracefully
  x86/boot: Fix boot failure when SMP MP-table is based at 0
  x86/mm: Limit mmap() of /dev/mem to valid physical addresses
  x86/selftests: Add test for mapping placement for 5-level paging
  ...

7 years agoMerge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 21:43:25 +0000 (13:43 -0800)]
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Ingo Molnar:
 "Misc fixes: a documentation fix, a Sparse warning fix and a debugging
  fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/debug: Fix task state recording/printout
  sched/deadline: Don't use dubious signed bitfields
  sched/deadline: Fix the description of runtime accounting in the documentation

7 years agoMerge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 21:41:48 +0000 (13:41 -0800)]
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fixes from Ingo Molnar:
 "Misc fixes: two PMU driver fixes and a memory leak fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix memory leak triggered by perf --namespace
  perf/x86/intel/uncore: Add event constraint for BDX PCU
  perf/x86/intel: Hide TSX events when RTM is not supported

7 years agoMerge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 21:36:54 +0000 (13:36 -0800)]
Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull static key fix from Ingo Molnar:
 "Fix a boot warning related to bad init ordering of the static keys
  self-test"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  jump_label: Invoke jump_label_test() via early_initcall()

7 years agoMerge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sun, 26 Nov 2017 21:11:18 +0000 (13:11 -0800)]
Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool fixes from Ingo Molnar:
 "A handful of objtool fixes, most of them related to making the UAPI
  header-syncing warnings easier to read and easier to act upon"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools/headers: Sync objtool UAPI header
  objtool: Fix cross-build
  objtool: Move kernel headers/code sync check to a script
  objtool: Move synced files to their original relative locations
  objtool: Make unreachable annotation inline asms explicitly volatile
  objtool: Add a comment for the unreachable annotation macros

7 years agoARM: BUG if jumping to usermode address in kernel mode
Russell King [Fri, 24 Nov 2017 23:49:34 +0000 (23:49 +0000)]
ARM: BUG if jumping to usermode address in kernel mode

Detect if we are returning to usermode via the normal kernel exit paths
but the saved PSR value indicates that we are in kernel mode.  This
could occur due to corrupted stack state, which has been observed with
"ftracetest".

This ensures that we catch the problem case before we get to user code.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
7 years agoMerge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
Linus Torvalds [Sat, 25 Nov 2017 18:37:16 +0000 (08:37 -1000)]
Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:

 - The final conversion of timer wheel timers to timer_setup().

   A few manual conversions and a large coccinelle assisted sweep and
   the removal of the old initialization mechanisms and the related
   code.

 - Remove the now unused VSYSCALL update code

 - Fix permissions of /proc/timer_list. I still need to get rid of that
   file completely

 - Rename a misnomed clocksource function and remove a stale declaration

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
  m68k/macboing: Fix missed timer callback assignment
  treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts
  timer: Remove redundant __setup_timer*() macros
  timer: Pass function down to initialization routines
  timer: Remove unused data arguments from macros
  timer: Switch callback prototype to take struct timer_list * argument
  timer: Pass timer_list pointer to callbacks unconditionally
  Coccinelle: Remove setup_timer.cocci
  timer: Remove setup_*timer() interface
  timer: Remove init_timer() interface
  treewide: setup_timer() -> timer_setup() (2 field)
  treewide: setup_timer() -> timer_setup()
  treewide: init_timer() -> setup_timer()
  treewide: Switch DEFINE_TIMER callbacks to struct timer_list *
  s390: cmm: Convert timers to use timer_setup()
  lightnvm: Convert timers to use timer_setup()
  drivers/net: cris: Convert timers to use timer_setup()
  drm/vc4: Convert timers to use timer_setup()
  block/laptop_mode: Convert timers to use timer_setup()
  net/atm/mpc: Avoid open-coded assignment of timer callback function
  ...

7 years agoMerge tag 'arc-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Linus Torvalds [Sat, 25 Nov 2017 18:21:54 +0000 (08:21 -1000)]
Merge tag 'arc-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull ARC updates from Vineet Gupta:

 - more changes for HS48 cores: supporting MMUv5, detecting new
   micro-arch gizmos

 - axs10x platform wiring up reset driver merged in this cycle

 - ARC perf driver optimizations

* tag 'arc-4.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: perf: avoid vmalloc backed mmap
  ARCv2: perf: optimize given that num counters <= 32
  ARCv2: perf: tweak overflow interrupt
  ARC: [plat-axs10x] DTS: Add reset controller node to manage ethernet reset
  ARCv2: boot log: updates for HS48: dual-issue, ECC, Loop Buffer
  ARCv2: Accomodate HS48 MMUv5 by relaxing MMU ver checking
  ARC: [plat-axs10x] auto-select AXS101 or AXS103 given the  ISA config

7 years agoMerge tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy...
Linus Torvalds [Sat, 25 Nov 2017 18:06:30 +0000 (08:06 -1000)]
Merge tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - use 'pwd' instead of '/bin/pwd' for portability

 - clean up Makefiles

 - fix ld-option for clang

 - fix malloc'ed data size in Kconfig

 - fix parallel building along with coccicheck

 - fix a minor issue of package building

 - prompt to use "rpm-pkg" instead of "rpm"

 - clean up *.i and *.lst patterns by "make clean"

* tag 'kbuild-v4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: drop $(extra-y) from real-objs-y
  kbuild: clean up *.i and *.lst patterns by make clean
  kbuild: rpm: prompt to use "rpm-pkg" if "rpm" target is used
  kbuild: pkg: use --transform option to prefix paths in tar
  coccinelle: fix parallel build with CHECK=scripts/coccicheck
  kconfig/symbol.c: use correct pointer type argument for sizeof
  kbuild: Set KBUILD_CFLAGS before incl. arch Makefile
  kbuild: remove all dummy assignments to obj-
  kbuild: create built-in.o automatically if parent directory wants it
  kbuild: /bin/pwd -> pwd

7 years agoMerge tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowe...
Linus Torvalds [Sat, 25 Nov 2017 17:58:25 +0000 (07:58 -1000)]
Merge tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull AFS fixes from David Howells:

 - Make AFS file locking work again.

 - Don't write to a page that's being written out, but wait for it to
   complete.

 - Do d_drop() and d_add() in the right places.

 - Put keys on error paths.

 - Remove some redundant code.

* tag 'afs-fixes-20171124' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: remove redundant assignment of dvnode to itself
  afs: cell: Remove unnecessary code in afs_lookup_cell
  afs: Fix signal handling in some file ops
  afs: Fix some dentry handling in dir ops and missing key_puts
  afs: Make afs_write_begin() avoid writing to a page that's being stored
  afs: Fix file locking

7 years agoMerge tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Linus Torvalds [Sat, 25 Nov 2017 05:44:25 +0000 (19:44 -1000)]
Merge tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Radim Krčmář:
 "Trimmed second batch of KVM changes for Linux 4.15:

   - GICv4 Support for KVM/ARM

   - re-introduce support for CPUs without virtual NMI (cc stable) and
     allow testing of KVM without virtual NMI on available CPUs

   - fix long-standing performance issues with assigned devices on AMD
     (cc stable)"

* tag 'kvm-4.15-2' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (30 commits)
  kvm: vmx: Allow disabling virtual NMI support
  kvm: vmx: Reinstate support for CPUs without virtual NMI
  KVM: SVM: obey guest PAT
  KVM: arm/arm64: Don't queue VLPIs on INV/INVALL
  KVM: arm/arm64: Fix GICv4 ITS initialization issues
  KVM: arm/arm64: GICv4: Theory of operations
  KVM: arm/arm64: GICv4: Enable VLPI support
  KVM: arm/arm64: GICv4: Prevent userspace from changing doorbell affinity
  KVM: arm/arm64: GICv4: Prevent a VM using GICv4 from being saved
  KVM: arm/arm64: GICv4: Enable virtual cpuif if VLPIs can be delivered
  KVM: arm/arm64: GICv4: Hook vPE scheduling into vgic flush/sync
  KVM: arm/arm64: GICv4: Use the doorbell interrupt as an unblocking source
  KVM: arm/arm64: GICv4: Add doorbell interrupt handling
  KVM: arm/arm64: GICv4: Use pending_last as a scheduling hint
  KVM: arm/arm64: GICv4: Handle INVALL applied to a vPE
  KVM: arm/arm64: GICv4: Propagate property updates to VLPIs
  KVM: arm/arm64: GICv4: Handle MOVALL applied to a vPE
  KVM: arm/arm64: GICv4: Handle CLEAR applied to a VLPI
  KVM: arm/arm64: GICv4: Propagate affinity changes to the physical ITS
  KVM: arm/arm64: GICv4: Unmap VLPI when freeing an LPI
  ...

7 years agoMerge tag 'powerpc-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...
Linus Torvalds [Sat, 25 Nov 2017 05:40:12 +0000 (19:40 -1000)]
Merge tag 'powerpc-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "A small batch of fixes, about 50% tagged for stable and the rest for
  recently merged code.

  There's one more fix for the >128T handling on hash. Once a process
  had requested a single mmap above 128T we would then always search
  above 128T. The correct behaviour is to consider the hint address in
  isolation for each mmap request.

  Then a couple of fixes for the IMC PMU, a missing EXPORT_SYMBOL in
  VAS, a fix for STRICT_KERNEL_RWX on 32-bit, and a fix to correctly
  identify P9 DD2.1 but in code that is currently not used by default.

  Thanks to: Aneesh Kumar K.V, Christophe Leroy, Madhavan Srinivasan,
  Sukadev Bhattiprolu"

* tag 'powerpc-4.15-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Fix Power9 DD2.1 logic in DT CPU features
  powerpc/perf: Fix IMC_MAX_PMU macro
  powerpc/perf: Fix pmu_count to count only nest imc pmus
  powerpc: Fix boot on BOOK3S_32 with CONFIG_STRICT_KERNEL_RWX
  powerpc/perf/imc: Use cpu_to_node() not topology_physical_package_id()
  powerpc/vas: Export chip_to_vas_id()
  powerpc/64s/slice: Use addr limit when computing slice mask

7 years agoMerge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target...
Linus Torvalds [Sat, 25 Nov 2017 05:19:20 +0000 (19:19 -1000)]
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

Pull SCSI target updates from Nicholas Bellinger:

 "This series is predominantly bug-fixes, with a few small improvements
  that have been outstanding over the last release cycle.

  As usual, the associated bug-fixes have CC' tags for stable.

  Also, things have been particularly quiet wrt new developments the
  last months, with most folks continuing to focus on stability atop 4.x
  stable kernels for their respective production configurations.

  Also at this point, the stable trees have been synced up with
  mainline. This will continue to be a priority, as production users
  tend to run exclusively atop stable kernels, a few releases behind
  mainline.

  The highlights include:

   - Fix PR PREEMPT_AND_ABORT null pointer dereference regression in
     v4.11+ (tangwenji)

   - Fix OOPs during removing TCMU device (Xiubo Li + Zhang Zhuoyu)

   - Add netlink command reply supported option for each device (Kenjiro
     Nakayama)

   - cxgbit: Abort the TCP connection in case of data out timeout (Varun
     Prakash)

   - Fix PR/ALUA file path truncation (David Disseldorp)

   - Fix double se_cmd completion during ->cmd_time_out (Mike Christie)

   - Fix QUEUE_FULL + SCSI task attribute handling in 4.1+ (Bryant Ly +
     nab)

   - Fix quiese during transport_write_pending_qf endless loop (nab)

   - Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK in 3.14+
     (Don White + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (35 commits)
  tcmu: Add a missing unlock on an error path
  tcmu: Fix some memory corruption
  iscsi-target: Fix non-immediate TMR reference leak
  iscsi-target: Make TASK_REASSIGN use proper se_cmd->cmd_kref
  target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK
  target: Fix quiese during transport_write_pending_qf endless loop
  target: Fix caw_sem leak in transport_generic_request_failure
  target: Fix QUEUE_FULL + SCSI task attribute handling
  iSCSI-target: Use common error handling code in iscsi_decode_text_input()
  target/iscsi: Detect conn_cmd_list corruption early
  target/iscsi: Fix a race condition in iscsit_add_reject_from_cmd()
  target/iscsi: Modify iscsit_do_crypto_hash_buf() prototype
  target/iscsi: Fix endianness in an error message
  target/iscsi: Use min() in iscsit_dump_data_payload() instead of open-coding it
  target/iscsi: Define OFFLOAD_BUF_SIZE once
  target: Inline transport_put_cmd()
  target: Suppress gcc 7 fallthrough warnings
  target: Move a declaration of a global variable into a header file
  tcmu: fix double se_cmd completion
  target: return SAM_STAT_TASK_SET_FULL for TCM_OUT_OF_RESOURCES
  ...

7 years agom68k/macboing: Fix missed timer callback assignment
Kees Cook [Thu, 23 Nov 2017 22:19:02 +0000 (14:19 -0800)]
m68k/macboing: Fix missed timer callback assignment

This fixes a missed function prototype callback from the timer conversions.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20171123221902.GA75727@beast
7 years agoafs: remove redundant assignment of dvnode to itself
Colin Ian King [Mon, 20 Nov 2017 13:58:20 +0000 (13:58 +0000)]
afs: remove redundant assignment of dvnode to itself

The assignment of dvnode to itself is redundant and can be removed.
Cleans up warning detected by cppcheck:

fs/afs/dir.c:975: (warning) Redundant assignment of 'dvnode' to itself.

Fixes: d2ddc776a458 ("afs: Overhaul volume and server record caching and fileserver rotation")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
7 years agoafs: cell: Remove unnecessary code in afs_lookup_cell
Gustavo A. R. Silva [Fri, 17 Nov 2017 22:40:32 +0000 (16:40 -0600)]
afs: cell: Remove unnecessary code in afs_lookup_cell

Due to recent changes this piece of code is no longer needed.

Addresses-Coverity-ID: 1462033
Link: https://lkml.kernel.org/r/4923.1510957307@warthog.procyon.org.uk
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
7 years agoafs: Fix signal handling in some file ops
David Howells [Mon, 20 Nov 2017 22:41:00 +0000 (22:41 +0000)]
afs: Fix signal handling in some file ops

afs_mkdir(), afs_create(), afs_link() and afs_symlink() all need to drop
the target dentry if a signal causes the operation to be killed immediately
before we try to contact the server.

Signed-off-by: David Howells <dhowells@redhat.com>
7 years agoafs: Fix some dentry handling in dir ops and missing key_puts
David Howells [Mon, 20 Nov 2017 23:04:08 +0000 (23:04 +0000)]
afs: Fix some dentry handling in dir ops and missing key_puts

Fix some of dentry handling in AFS directory ops:

 (1) Do d_drop() on the new_dentry before assigning a new inode to it in
     afs_vnode_new_inode().  It's fine to do this before calling afs_iget()
     because the operation has taken place on the server.

 (2) Replace d_instantiate()/d_rehash() with d_add().

 (3) Don't d_drop() the new_dentry in afs_rename() on error.

Also fix afs_link() and afs_rename() to call key_put() on all error paths
where the key is taken.

Signed-off-by: David Howells <dhowells@redhat.com>
7 years agoafs: Make afs_write_begin() avoid writing to a page that's being stored
David Howells [Sat, 18 Nov 2017 00:13:30 +0000 (00:13 +0000)]
afs: Make afs_write_begin() avoid writing to a page that's being stored

Make afs_write_begin() wait for a page that's marked PG_writeback because:

 (1) We need to avoid interference with the data being stored so that the
     data on the server ends up in a defined state.

 (2) page->private is used to track the window of dirty data within a page,
     but it's also used by the storage code to track what's being written,
     being cleared by the completion notification.  Ownership can't be
     relinquished by the storage code until completion because it a store
     fails, the data must be remarked dirty.

Tracing shows something like the following (edited):

 x86_64-linux-gn-15940 [1] afs_page_dirty: vn=ffff8800bef33800 9c75 begin 0-125
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 store+ 0-125
 x86_64-linux-gn-15940 [1] afs_page_dirty: vn=ffff8800bef33800 9c75 begin 0-2052
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 clear 0-2052
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 store 0-0
    kworker/u8:3-114   [2] afs_page_dirty: vn=ffff8800bef33800 9c75 WARN 0-0

The clear (completion) corresponding to the store+ (store continuation from
a previous page) happens between the second begin (afs_write_begin) and the
store corresponding to that.  This results in the second store not seeing
any data to write back, leading to the following warning:

WARNING: CPU: 2 PID: 114 at ../fs/afs/write.c:403 afs_write_back_from_locked_page+0x19d/0x76c [kafs]
Modules linked in: kafs(E)
CPU: 2 PID: 114 Comm: kworker/u8:3 Tainted: G            E   4.14.0-fscache+ #242
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Workqueue: writeback wb_workfn (flush-afs-2)
task: ffff8800cad72600 task.stack: ffff8800cad44000
RIP: 0010:afs_write_back_from_locked_page+0x19d/0x76c [kafs]
RSP: 0018:ffff8800cad47aa0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff8800bef33a20 RCX: 0000000000000000
RDX: 000000000000000f RSI: ffffffff81c5d0e0 RDI: ffff8800cad72e78
RBP: ffff8800d31ea1e8 R08: ffff8800c1358000 R09: ffff8800ca00e400
R10: ffff8800cad47a38 R11: ffff8800c5d9e400 R12: 0000000000000000
R13: ffffea0002d9df00 R14: ffffffffa0023c1c R15: 0000000000007fdf
FS:  0000000000000000(0000) GS:ffff8800ca700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f85ac6c4000 CR3: 0000000001c10001 CR4: 00000000001606e0
Call Trace:
 ? clear_page_dirty_for_io+0x23a/0x267
 afs_writepages_region+0x1be/0x286 [kafs]
 afs_writepages+0x60/0x127 [kafs]
 do_writepages+0x36/0x70
 __writeback_single_inode+0x12f/0x635
 writeback_sb_inodes+0x2cc/0x452
 __writeback_inodes_wb+0x68/0x9f
 wb_writeback+0x208/0x470
 ? wb_workfn+0x22b/0x565
 wb_workfn+0x22b/0x565
 ? worker_thread+0x230/0x2ac
 process_one_work+0x2cc/0x517
 ? worker_thread+0x230/0x2ac
 worker_thread+0x1d4/0x2ac
 ? rescuer_thread+0x29b/0x29b
 kthread+0x15d/0x165
 ? kthread_create_on_node+0x3f/0x3f
 ? call_usermodehelper_exec_async+0x118/0x11f
 ret_from_fork+0x24/0x30

Signed-off-by: David Howells <dhowells@redhat.com>
7 years agosched/debug: Fix task state recording/printout
Thomas Gleixner [Wed, 22 Nov 2017 12:05:48 +0000 (13:05 +0100)]
sched/debug: Fix task state recording/printout

The recent conversion of the task state recording to use task_state_index()
broke the sched_switch tracepoint task state output.

task_state_index() returns surprisingly an index (0-7) which is then
printed with __print_flags() applying bitmasks. Not really working and
resulting in weird states like 'prev_state=t' instead of 'prev_state=I'.

Use TASK_REPORT_MAX instead of TASK_STATE_MAX to report preemption. Build a
bitmask from the return value of task_state_index() and store it in
entry->prev_state, which makes __print_flags() work as expected.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: stable@vger.kernel.org
Fixes: efb40f588b43 ("sched/tracing: Fix trace_sched_switch task-state printing")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1711221304180.1751@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
7 years agox86/decoder: Add new TEST instruction pattern
Masami Hiramatsu [Fri, 24 Nov 2017 04:56:30 +0000 (13:56 +0900)]
x86/decoder: Add new TEST instruction pattern

The kbuild test robot reported this build warning:

  Warning: arch/x86/tools/test_get_len found difference at <jump_table>:ffffffff8103dd2c

  Warning: ffffffff8103dd82: f6 09 d8 testb $0xd8,(%rcx)
  Warning: objdump says 3 bytes, but insn_get_length() says 2
  Warning: decoded and checked 1569014 instructions with 1 warnings

This sequence seems to be a new instruction not in the opcode map in the Intel SDM.

The instruction sequence is "F6 09 d8", means Group3(F6), MOD(00)REG(001)RM(001), and 0xd8.
Intel SDM vol2 A.4 Table A-6 said the table index in the group is "Encoding of Bits 5,4,3 of
the ModR/M Byte (bits 2,1,0 in parenthesis)"

In that table, opcodes listed by the index REG bits as:

  000         001       010 011  100        101        110         111
 TEST Ib/Iz,(undefined),NOT,NEG,MUL AL/rAX,IMUL AL/rAX,DIV AL/rAX,IDIV AL/rAX

So, it seems TEST Ib is assigned to 001.

Add the new pattern.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
7 years agoMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Linus Torvalds [Fri, 24 Nov 2017 07:18:46 +0000 (21:18 -1000)]
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

Pull networking fixes from David Miller:

 1) Fix PCI IDs of 9000 series iwlwifi devices, from Luca Coelho.

 2) bpf offload bug fixes from Jakub Kicinski.

 3) Fix bpf verifier to NOP out code which is dead at run time because
    due to branch pruning the verifier will not explore such
    instructions. From Alexei Starovoitov.

 4) Fix crash when deleting secondary chains in packet scheduler
    classifier. From Roman Kapl.

 5) Fix buffer management bugs in smc, from Ursula Braun.

 6) Fix regression in anycast route handling, from David Ahern.

 7) Fix link settings regression in r8169, from Tobias Jakobi.

 8) Add back enough UFO support so that live migration still works, from
    Willem de Bruijn.

 9) Linearize enough packet data for the full extent to which the ipvlan
    code will inspect the packet headers, from Gao Feng.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (46 commits)
  ipvlan: Fix insufficient skb linear check for ipv6 icmp
  ipvlan: Fix insufficient skb linear check for arp
  geneve: only configure or fill UDP_ZERO_CSUM6_RX/TX info when CONFIG_IPV6
  net: dsa: bcm_sf2: Clear IDDQ_GLOBAL_PWR bit for PHY
  net: accept UFO datagrams from tuntap and packet
  net: realtek: r8169: implement set_link_ksettings()
  net: ipv6: Fixup device for anycast routes during copy
  net/smc: Fix preinitialization of buf_desc in __smc_buf_create()
  net/smc: use sk_rcvbuf as start for rmb creation
  ipv6: Do not consider linkdown nexthops during multipath
  net: sched: fix crash when deleting secondary chains
  net: phy: cortina: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE
  bpf: fix branch pruning logic
  bpf: change bpf_perf_event_output arg5 type to ARG_CONST_SIZE_OR_ZERO
  bpf: change bpf_probe_read_str arg2 type to ARG_CONST_SIZE_OR_ZERO
  bpf: remove explicit handling of 0 for arg2 in bpf_probe_read
  bpf: introduce ARG_PTR_TO_MEM_OR_NULL
  i40evf: Use smp_rmb rather than read_barrier_depends
  fm10k: Use smp_rmb rather than read_barrier_depends
  igb: Use smp_rmb rather than read_barrier_depends
  ...

7 years agoMerge tag 'platform-drivers-x86-v4.15-2' of git://git.infradead.org/linux-platform...
Linus Torvalds [Fri, 24 Nov 2017 07:14:30 +0000 (21:14 -1000)]
Merge tag 'platform-drivers-x86-v4.15-2' of git://git.infradead.org/linux-platform-drivers-x86

Pull x86 platform driver fixes from Darren Hart:
 "Fix two issues resulting from the dell-smbios refactoring and
  introduction of the dell-smbios-wmi dispatcher.

  The first ensures a proper error code is returned when kzalloc fails.

  The second avoids an issue in older Dell BIOS implementations which
  would fail if the more complex calls were made by limiting those
  platforms to the simple calls such as those used by the existing
  dell-laptop and dell-wmi drivers, preserving their functionality prior
  to the addition of the dell-smbios-wmi dispatcher"

* tag 'platform-drivers-x86-v4.15-2' of git://git.infradead.org/linux-platform-drivers-x86:
  platform/x86: dell-laptop: fix error return code in dell_init()
  platform/x86: dell-smbios-wmi: Disable userspace interface if missing hotfix

7 years agoMerge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Linus Torvalds [Fri, 24 Nov 2017 07:12:58 +0000 (21:12 -1000)]
Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI fixes from James Bottomley:
 "Two basic fixes: one for the sparse problem with the blacklist flags
  and another for a hang forever in bnx2i"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: Use 'blist_flags_t' for scsi_devinfo flags
  scsi: bnx2fc: Fix hung task messages when a cleanup response is not received during abort