Martin Kaiser [Wed, 11 Aug 2021 20:14:49 +0000 (22:14 +0200)]
staging: r8188eu: use proper way to build a module
It seems that for now, we can only build this driver as a module.
Use the same mechanism as other drivers (such as rtl8723bs or the
deprecated rtl8188eu) to enforce building as a module, i.e. depend on m
in Kconfig instead of setting CONFIG_R8188EU = m in the Makefile.
If we set CONFIG_R8188EU in the Makefile, this setting will not be visible
in .config.
Tuo Li [Wed, 11 Aug 2021 03:11:35 +0000 (20:11 -0700)]
staging: rtl8192e: rtl_core: Fix possible null-pointer dereference in _rtl92e_pci_disconnect()
The variable dev is checked in:
if (dev)
This indicates that it can be NULL. If so, a null-pointer dereference will
occur:
priv = rtllib_priv(dev);
However, the value of priv is not used in the remaining part of this
function. Thus the else-branch can be removed to fix this posible
null-pointer dereference.
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn> Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Tuo Li <islituo@gmail.com> Link: https://lore.kernel.org/r/20210811031135.4110-1-islituo@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Nathan Chancellor [Wed, 11 Aug 2021 00:55:05 +0000 (17:55 -0700)]
staging: r8188eu: os_dep: Hoist vmalloc.h include into osdep_service.h
After commit 71f09c5ae9d2 ("staging: r8188eu: Remove wrapper around
vfree"), the driver fails to build on Hexagon due to an implicit
declaration in several different files:
drivers/staging/r8188eu/core/rtw_mlme.c:129:3: error: implicit
declaration of function 'vfree'
[-Werror,-Wimplicit-function-declaration]
vfree(pmlmepriv->free_bss_buf);
^
1 error generated.
Previously, vfree() was only called in osdep_service.c, which includes
vmalloc.h for vmalloc() and vfree(). Now, the driver relies on vfree()
getting implicitly included from another file.
Hoist the vmalloc.h include from osdep_service.c to osdep_service.h so
that the driver continues to build fine on all architectures.
Yang Yingliang [Tue, 10 Aug 2021 12:53:14 +0000 (20:53 +0800)]
staging: r8188eu: Use GFP_ATOMIC under spin lock
A spin lock is taken in __nat25_db_network_insert() and
update_BCNTIM() is called under spin lock so we should
use GFP_ATOMIC in both place.
Fixes: 15865124feed ("staging: r8188eu: introduce new core dir for RTL8188eu driver") Reported-by: Hulk Robot <hulkci@huawei.com> Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Link: https://lore.kernel.org/r/20210810125314.2182112-1-yangyingliang@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Larry Finger [Tue, 10 Aug 2021 18:05:11 +0000 (13:05 -0500)]
staging: r8188eu: Replace BITn with BIT(n)
The driver uses BITn instead of BIT(n). All such usage is converted.
Note that this patch does not address any warnings that checkpatch
will find. These include missing space around operators and lines
that are too long. These problems will be addressed in a separate
patch.
Phillip Potter [Tue, 10 Aug 2021 23:50:47 +0000 (00:50 +0100)]
staging: r8188eu: remove lines from Makefile that silence build warnings
Remove the several lines from the Makefile that append EXTRA_CFLAGS options
to silence build warnings about unused variables, unused functions and such
like. This will enable cleanup of missed warnings, and easier spotting
of future such problems.
Phillip Potter [Tue, 10 Aug 2021 23:50:40 +0000 (00:50 +0100)]
staging: r8188eu: remove unused functions from os_dep/ioctl_linux.c
Remove unused functions that are now no longer called as a result of the
removal of rtw_ioctl in a previous patch. This includes functions not
directly called from rtw_ioctl, but anything in that specific
call-chain.
Phillip Potter [Tue, 10 Aug 2021 07:45:04 +0000 (08:45 +0100)]
staging: r8188eu: remove rtw_ioctl function
Remove rtw_ioctl function from os_dep/ioctl_linux.c, its declaration
in include/osdep_intf.h, and finally its inclusion as the value of the
.ndo_do_ioctl member of struct net_device_ops rtw_netdev_ops in
os_dep/os_intfs.c.
The e-mail from Arnd Bergmann at:
https://lore.kernel.org/linux-next/CAK8P3a0WRMNmBmBDerZ0nWPdFZKALnxrj-uUFBkTP-MOtv48vg@mail.gmail.com
explains the justification for this approach. Essentially, changes from
net-next make the existing function and its use of SIOCDEVPRIVATE ioctls
unworkable without changes.
Functions called from rtw_ioctl that are now no longer accessible will
be cleaned up in further patches. Additionally, once these changes have
made their way downstream to the staging branch, we can modify and
reconnect rtw_android_priv_cmd via ndo_siocdevprivate in struct
net_device_ops.
Martin Kaiser [Sat, 7 Aug 2021 15:36:34 +0000 (17:36 +0200)]
staging: r8188eu: use IW_HANDLER to declare wext handlers
Use the IW_HANDLER macro to declare the handler functions for
wext ioctls. We don't have to skip unused ioctl numbers manually.
The same modification was applied to the deprecated rtl8188eu driver in
commit af249fce390f ("staging: rtl8188eu: use IW_HANDLER to declare wext
handlers").
Martin Kaiser [Sat, 7 Aug 2021 15:36:28 +0000 (17:36 +0200)]
staging: r8188eu: remove empty function
With the RT_TRACE print removed, the rtw_wx_set_freq function is now
empty.
This function should be removed. At the moment, the setfreq ioctl
returns success to the caller although the frequency wasn't set.
It makes more sense to inform callers that this driver does not
support setfreq.
Fabio Aiuto [Sat, 7 Aug 2021 09:48:07 +0000 (11:48 +0200)]
staging: rtl8723bs: remove rf type branching (fourth patch)
remove all function calls to rtw_get_hw_reg made to
read HW_VAR_RF_TYPE and get value of rt_type, which
is always 1T1R. Clean up code on removal sites,
keeping 1T1R code unconditionally.
Fabio Aiuto [Sat, 7 Aug 2021 09:48:04 +0000 (11:48 +0200)]
staging: rtl8723bs: remove rf type branching (first patch)
remove rf type branching, for the baseband works only on
1T1R rf type, so just keep code branches related to 1T1R.
Remove RFType from hal_version struct, and all
related code.
Fabio Aiuto [Sat, 7 Aug 2021 09:48:01 +0000 (11:48 +0200)]
staging: rtl8723bs: clean driver from unused RF paths
rtl8723bs support only two rf paths (A and B), remove all
the others (C, D, BC, ...) as they are unused. Keep
just one enum selecting rf path, remove unused macro
indicating max rf path number, add an item in rf_path
enum for this pourpose.
Fabio Aiuto [Sat, 7 Aug 2021 09:47:55 +0000 (11:47 +0200)]
staging: rtl8723bs: do some code cleaning in modified function
do some code cleaning after changes of previous commit.
Fixed comments, camel case names, variable naming conventions;
kept function names without chip series numbers (this is
just code for 8723), fixed indentations, blank lines and
other minor stuff.
Larry Finger [Fri, 6 Aug 2021 21:32:35 +0000 (16:32 -0500)]
staging: r8188eu: Fix potential memory leak or NULL dereference
In routine c2h_wk_callback(() following a kmalloc() call, the
error recovery is flawed. If the kmalloc() returns a pointer
that is not NULL, and the following c2h_evt_read() fails, the
code will leak that buffer. If the kmalloc() fails, a NULL
dereference will occur in the following code.
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Adjust memcpy() destination to be the named structure itself, rather than
the first member, allowing memcpy() to correctly reason about the size.
"objdump -d" shows no object code changes.
Cc: Ross Schmidt <ross.schm.dev@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: devel@driverdev.osuosl.org Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210806201422.2871679-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Split the 3 addr memcpy() into 3 memcpy() calls so the compiler doesn't
think an overflowing memcpy() happens against the addr1 field (the
neighbors are intended to be copied as well).
ieee80211_read_qos_param_element() copies a struct ieee80211_info_element
into a struct ieee80211_qos_information_element, but is actually wanting to
copy into the larger struct ieee80211_qos_parameter_info (the contents of
ac_params_record[] is later examined). Refactor the routine to perform
centralized checks, and copy the entire contents directly (since the id
and len members match the elementID and length members):
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.
Split the 3 addr memcpy() into 3 memcpy() calls so the compiler doesn't
think an overflowing memcpy() happens against the addr1 field (the
neighbors are intended to be copied as well).
rtllib_read_qos_param_element() copies a struct rtllib_info_element
into a struct rtllib_qos_information_element, but is actually wanting to
copy into the larger struct rtllib_qos_parameter_info (the contents of
ac_params_record[] is later examined). Refactor the routine to perform
centralized checks, and copy the entire contents directly (since the id
and len members match the elementID and length members):
Ojaswin Mujoo [Mon, 2 Aug 2021 17:42:11 +0000 (23:12 +0530)]
staging: vchiq: Add details to Kconfig help texts
Add some details to the Kconfig definitions of $CONFIG_VCHIQ_CDEV and
$CONFIG_BCM2835_VCHIQ to help make the motive behind the configs a bit
more clear.
Ojaswin Mujoo [Mon, 2 Aug 2021 17:42:10 +0000 (23:12 +0530)]
staging: vchiq: Set $CONFIG_BCM2835_VCHIQ to imply $CONFIG_VCHIQ_CDEV
Before $CONFIG_VCHIQ_CDEV was defined, the vchiq cdev used to be created
unconditionally when CONFIG_BCM2835_VCHIQ=y. When an earlier commit
introduced the new config, its default behavior was set to disabled,
which might surprise some unsuspecting users. Hence, modify
CONFIG_BCM2835_VCHIQ to imply CONFIG_VCHIQ_CDEV
Linus Torvalds [Sun, 8 Aug 2021 18:53:30 +0000 (11:53 -0700)]
Merge tag 'timers-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
"A single timer fix:
- Prevent a memory ordering issue in the timer expiry code which
makes it possible to observe falsely that the callback has been
executed already while that's not the case, which violates the
guarantee of del_timer_sync()"
* tag 'timers-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timers: Move clearing of base::timer_running under base:: Lock
Linus Torvalds [Sun, 8 Aug 2021 18:46:13 +0000 (11:46 -0700)]
Merge tag 'perf-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Thomas Gleixner:
"A set of perf fixes:
- Correct the permission checks for perf event which send SIGTRAP to
a different process and clean up that code to be more readable.
- Prevent an out of bound MSR access in the x86 perf code which
happened due to an incomplete limiting to the actually available
hardware counters.
- Prevent access to the AMD64_EVENTSEL_HOSTONLY bit when running
inside a guest.
- Handle small core counter re-enabling correctly by issuing an ACK
right before reenabling it to prevent a stale PEBS record being
kept around"
* tag 'perf-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel: Apply mid ACK for small core
perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
perf/x86: Fix out of bound MSR access
perf: Refactor permissions check into perf_check_permission()
perf: Fix required permissions if sigtrap is requested
Linus Torvalds [Sun, 8 Aug 2021 17:41:49 +0000 (10:41 -0700)]
Merge tag 'char-misc-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc driver fixes from Greg KH:
"Here are some small char/misc driver fixes for 5.14-rc5.
They resolve a few regressions that people reported:
- acrn driver fix
- fpga driver fix
- interconnect tiny driver fixes
All have been in linux-next for a while with no reported issues"
* tag 'char-misc-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
interconnect: Fix undersized devress_alloc allocation
interconnect: qcom: icc-rpmh: Add BCMs to commit list in pre_aggregate
interconnect: qcom: icc-rpmh: Ensure floor BW is enforced for all nodes
fpga: dfl: fme: Fix cpu hotplug issue in performance reporting
virt: acrn: Do hcall_destroy_vm() before resource release
interconnect: Always call pre_aggregate before aggregate
interconnect: Zero initial BW after sync-state
Linus Torvalds [Sun, 8 Aug 2021 17:34:49 +0000 (10:34 -0700)]
Merge tag 'driver-core-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH:
"Here are three tiny driver core and firmware loader fixes for
5.14-rc5. They are:
- driver core fix for when probing fails
- firmware loader fixes for reported problems.
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
firmware_loader: fix use-after-free in firmware_fallback_sysfs
firmware_loader: use -ETIMEDOUT instead of -EAGAIN in fw_load_sysfs_fallback
drivers core: Fix oops when driver probe fails
Linus Torvalds [Sun, 8 Aug 2021 17:29:39 +0000 (10:29 -0700)]
Merge tag 'staging-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging
Pull staging driver fixes from Greg KH:
"Here are a few small staging driver fixes for 5.14-rc5 to resolve some
reported problems. They include:
- mt7621 driver fix
- rtl8723bs driver fixes
- rtl8712 driver fixes.
Nothing major, just small problems resolved.
All have been in linux-next for a while with no reported issues"
* tag 'staging-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: mt7621-pci: avoid to re-disable clock for those pcies not in use
staging: rtl8712: error handling refactoring
staging: rtl8712: get rid of flush_scheduled_work
staging: rtl8723bs: select CONFIG_CRYPTO_LIB_ARC4
staging: rtl8723bs: Fix a resource leak in sd_int_dpc
Linus Torvalds [Sun, 8 Aug 2021 17:23:13 +0000 (10:23 -0700)]
Merge tag 'tty-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial fixes from Greg KH:
"Here are some small tty/serial driver fixes for 5.14-rc5 to resolve a
number of reported problems.
They include:
- mips serial driver fixes
- 8250 driver fixes for reported problems
- fsl_lpuart driver fixes
- other tiny driver fixes
All have been in linux-next for a while with no reported problems"
* tag 'tty-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
serial: 8250_pci: Avoid irq sharing for MSI(-X) interrupts.
serial: 8250_mtk: fix uart corruption issue when rx power off
tty: serial: fsl_lpuart: fix the wrong return value in lpuart32_get_mctrl
serial: 8250_pci: Enumerate Elkhart Lake UARTs via dedicated driver
serial: 8250: fix handle_irq locking
serial: tegra: Only print FIFO error message when an error occurs
MIPS: Malta: Do not byte-swap accesses to the CBUS UART
serial: 8250: Mask out floating 16/32-bit bus bits
serial: max310x: Unprepare and disable clock in error path
Linus Torvalds [Sun, 8 Aug 2021 17:20:05 +0000 (10:20 -0700)]
Merge tag 'usb-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB driver fixes from Greg KH:
"Here are some small USB driver fixes for 5.14-rc5. They resolve a
number of small reported issues, including:
- cdnsp driver fixes
- usb serial driver fixes and device id updates
- usb gadget hid fixes
- usb host driver fixes
- usb dwc3 driver fixes
- other usb gadget driver fixes
All of these have been in linux-next for a while with no reported
issues"
* tag 'usb-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (21 commits)
usb: typec: tcpm: Keep other events when receiving FRS and Sourcing_vbus events
usb: dwc3: gadget: Avoid runtime resume if disabling pullup
usb: dwc3: gadget: Use list_replace_init() before traversing lists
USB: serial: ftdi_sio: add device ID for Auto-M3 OP-COM v2
USB: serial: pl2303: fix GT type detection
USB: serial: option: add Telit FD980 composition 0x1056
USB: serial: pl2303: fix HX type detection
USB: serial: ch341: fix character loss at high transfer rates
usb: cdnsp: Fix the IMAN_IE_SET and IMAN_IE_CLEAR macro
usb: cdnsp: Fixed issue with ZLP
usb: cdnsp: Fix incorrect supported maximum speed
usb: cdns3: Fixed incorrect gadget state
usb: gadget: f_hid: idle uses the highest byte for duration
Revert "thunderbolt: Hide authorized attribute if router does not support PCIe tunnels"
usb: otg-fsm: Fix hrtimer list corruption
usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses
usb: musb: Fix suspend and resume issues for PHYs on I2C and SPI
usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers
usb: gadget: f_hid: fixed NULL pointer dereference
usb: gadget: remove leaked entry from udc driver list
...
Linus Torvalds [Sat, 7 Aug 2021 17:34:26 +0000 (10:34 -0700)]
Merge tag 'io_uring-5.14-2021-08-07' of git://git.kernel.dk/linux-block
Pull io_uring from Jens Axboe:
"A few io-wq related fixes:
- Fix potential nr_worker race and missing max_workers check from one
path (Hao)
- Fix race between worker exiting and new work queue (me)"
* tag 'io_uring-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
io-wq: fix lack of acct->nr_workers < acct->max_workers judgement
io-wq: fix no lock protection of acct->nr_worker
io-wq: fix race between worker exiting and activating free worker
Linus Torvalds [Sat, 7 Aug 2021 17:26:21 +0000 (10:26 -0700)]
Merge tag 'block-5.14-2021-08-07' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
"A few minor fixes:
- Fix ldm kernel-doc warning (Bart)
- Fix adding offset twice for DMA address in n64cart (Christoph)
- Fix use-after-free in dasd path handling (Stefan)
- Order kyber insert trace correctly (Vincent)
- raid1 errored write handling fix (Wei)
- Fix blk-iolatency queue get failure handling (Yu)"
* tag 'block-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
kyber: make trace_block_rq call consistent with documentation
block/partitions/ldm.c: Fix a kernel-doc warning
blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
n64cart: fix the dma address in n64cart_do_bvec
s390/dasd: fix use after free in dasd path handling
md/raid10: properly indicate failure when ending a failed write request
Linus Torvalds [Sat, 7 Aug 2021 17:15:04 +0000 (10:15 -0700)]
Merge tag 'riscv-for-linus-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V fixes from Palmer Dabbelt:
- avoid dereferencing a null task pointer while walking the stack
- fix the memory size in the HiFive Unleashed device tree
- disable stack protectors when randstruct is enabled, which results in
non-deterministic offsets during module builds
- a pair of fixes to avoid relying on a constant physical memory base
for the non-XIP builds
* tag 'riscv-for-linus-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
Revert "riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED"
riscv: Get rid of CONFIG_PHYS_RAM_BASE in kernel physical address conversion
riscv: Disable STACKPROTECTOR_PER_TASK if GCC_PLUGIN_RANDSTRUCT is enabled
riscv: dts: fix memory size for the SiFive HiFive Unmatched
riscv: stacktrace: Fix NULL pointer dereference
The removal of this config exposes CONFIG_PHYS_RAM_BASE for all kernel
types: this value being implementation-specific, this breaks the
genericity of the RISC-V kernel so revert it.
riscv: Get rid of CONFIG_PHYS_RAM_BASE in kernel physical address conversion
The usage of CONFIG_PHYS_RAM_BASE for all kernel types was a mistake:
this value is implementation-specific and this breaks the genericity of
the RISC-V kernel.
Fix this by introducing a new variable phys_ram_base that holds this
value at runtime and use it in the kernel physical address conversion
macro. Since this value is used only for XIP kernels, evaluate it only if
CONFIG_XIP_KERNEL is set which in addition optimizes this macro for
standard kernels at compile-time.
Vincent Fu [Wed, 4 Aug 2021 19:49:23 +0000 (19:49 +0000)]
kyber: make trace_block_rq call consistent with documentation
The kyber ioscheduler calls trace_block_rq_insert() *after* the request
is added to the queue but the documentation for trace_block_rq_insert()
says that the call should be made *before* the request is added to the
queue. Move the tracepoint for the kyber ioscheduler so that it is
consistent with the documentation.
Linus Torvalds [Fri, 6 Aug 2021 19:55:07 +0000 (12:55 -0700)]
Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fixes from Ted Ts'o:
"A regression fix, bug fix, and a comment cleanup for ext4"
* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: fix potential htree corruption when growing large_dir directories
ext4: remove conflicting comment from __ext4_forget
ext4: fix potential uninitialized access to retval in kmmpd
Linus Torvalds [Fri, 6 Aug 2021 19:36:46 +0000 (12:36 -0700)]
Merge tag 'trace-v5.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Fix tracepoint race between static_call and callback data
As callbacks to a tracepoint are paired with the data that is passed
in when the callback is registered to the tracepoint, it must have
that data passed to the callback when the tracepoint is triggered,
else bad things will happen. To keep the two together, they are both
assigned to a tracepoint structure and added to an array. The
tracepoint call site will dereference the structure (via RCU) and call
the callback in that structure along with the data in that structure.
This keeps the callback and data tightly coupled.
Because of the overhead that retpolines have on tracepoint callbacks,
if there's only one callback attached to a tracepoint (a common case),
then it is called via a static call (code modified to do a direct call
instead of an indirect call). But to implement this, the data had to
be decoupled from the callback, as now the callback is implemented via
a direct call from the static call and not an indirect call from the
dereferenced structure.
Note, the static call only calls a callback used when there's a single
callback attached to the tracepoint. If more than one callback is
attached to the same tracepoint, then the static call will call an
iterator function that goes back to dereferencing the structure
keeping the callback and its data tightly coupled again.
Issues can arise when going from 0 callbacks to one, as the static
call is assigned to the callback, and it must take care that the data
passed to it is loaded before the static call calls the callback.
Going from 1 to 2 callbacks is not an issue, as long as the static
call is updated to the iterator before the tracepoint structure array
is updated via RCU. Going from 2 to more or back down to 2 is not an
issue as the iterator can handle all theses cases. But going from 2 to
1, care must be taken as the static call is now calling a callback and
the data that is loaded must be the data for that callback.
Care was taken to ensure the callback and data would be in-sync, but
after a bug was reported, it became clear that not enough was done to
make sure that was the case. These changes address this.
The first change is to compare the old and new data instead of the old
and new callback, as it's the data that can corrupt the callback, even
if the callback is the same (something getting freed).
The next change is to convert these transitions into states, to make
it easier to know when a synchronization is needed, and to perform
those synchronizations. The problem with this patch is that it slows
down disabling all events from under a second, to making it take over
10 seconds to do the same work. But that is addressed in the final
patch.
The final patch uses the RCU state functions to keep track of the RCU
state between the transitions, and only needs to perform the
synchronization if an RCU synchronization hasn't been done already.
This brings the performance of disabling all events back to its
original value. That's because no synchronization is required between
disabling tracepoints but is required when enabling a tracepoint after
its been disabled. If an RCU synchronization happens after the
tracepoint is disabled, and before it is re-enabled, there's no need
to do the synchronization again.
Both the second and third patch have subtle complexities that they are
separated into two patches. But because the second patch causes such a
regression in performance, the third patch adds a "Fixes" tag to the
second patch, such that the two must be backported together and not
just the second patch"
* tag 'trace-v5.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracepoint: Use rcu get state and cond sync for static call updates
tracepoint: Fix static call function vs data state mismatch
tracepoint: static call: Compare data on transition from 2->1 callees
Linus Torvalds [Fri, 6 Aug 2021 19:30:29 +0000 (12:30 -0700)]
Merge tag 'pm-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"Fix a recent regression in the timer events oriented (TEO) cpuidle
governor causing it to misbehave when idle state 0 is disabled and
rename two local variables for improved clarity on top of that"
* tag 'pm-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: teo: Rename two local variables in teo_select()
cpuidle: teo: Fix alternative idle state lookup
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