Kees Cook [Tue, 24 Aug 2021 00:00:17 +0000 (10:00 +1000)]
Compiler Attributes: add __alloc_size() for better bounds checking
Patch series "Add __alloc_size() for better bounds checking", v2.
GCC and Clang both use the "alloc_size" attribute to assist with bounds
checking around the use of allocation functions. Add the attribute,
adjust the Makefile to silence needless warnings, and add the hints to the
allocators where possible. These changes have been in use for a while now
in GrapheneOS.
This patch (of 2):
GCC and Clang can use the "alloc_size" attribute to better inform the
results of __builtin_object_size() (for compile-time constant values).
Clang can additionally use alloc_size to inform the results of
__builtin_dynamic_object_size() (for run-time values).
Because GCC sees the frequent use of struct_size() as an allocator size
argument, and notices it can return SIZE_MAX (the overflow indication), it
complains about these call sites may overflow (since SIZE_MAX is greater
than the default -Walloc-size-larger-than=PTRDIFF_MAX). This isn't
helpful since we already know a SIZE_MAX will be caught at run-time (this
was an intentional design). Instead, just disable this check as it is
both a false positive and redundant. (Clang does not have this warning
option.)
Link: https://lkml.kernel.org/r/20210818214021.2476230-1-keescook@chromium.org Link: https://lkml.kernel.org/r/20210818214021.2476230-2-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Christoph Lameter <cl@linux.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Dwaipayan Ray <dwaipayanray1@gmail.com> Cc: Joe Perches <joe@perches.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Christoph Hellwig [Tue, 24 Aug 2021 00:00:16 +0000 (10:00 +1000)]
mm: unexport {,un}lock_page_memcg
These are only used in built-in core mm code.
Link: https://lkml.kernel.org/r/20210820095815.445392-3-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Baolin Wang [Tue, 24 Aug 2021 00:00:16 +0000 (10:00 +1000)]
mm: migrate: fix the incorrect function name in comments
since commit a98a2f0c8ce1 ("mm/rmap: split migration into its own
function"), the migration ptes establishment has been split into a
separate try_to_migrate() function, thus update the related comments.
Baolin Wang [Tue, 24 Aug 2021 00:00:16 +0000 (10:00 +1000)]
mm: migrate: introduce a local variable to get the number of pages
Use thp_nr_pages() instead of compound_nr() to get the number of pages for
THP page, meanwhile introducing a local variable 'nr_pages' to avoid
getting the number of pages repeatedly.
Baolin Wang [Tue, 24 Aug 2021 00:00:15 +0000 (10:00 +1000)]
mm: migrate: simplify the file-backed pages validation when migrating its mapping
Patch series "Some cleanup for page migration", v3.
This patchset does some cleanups and improvements for page migration.
This patch (of 4):
There is no need to validate the file-backed page's refcount before trying
to freeze the page's expected refcount, instead we can rely on the
folio_ref_freeze() to validate if the page has the expected refcount
before migrating its mapping.
Moreover we are always under the page lock when migrating the page
mapping, which means nowhere else can remove it from the page cache, so we
can remove the xas_load() validation under the i_pages lock.
Matthew Wilcox (Oracle) [Tue, 24 Aug 2021 00:00:15 +0000 (10:00 +1000)]
mm: move kvmalloc-related functions to slab.h
Not all files in the kernel should include mm.h. Migrating callers from
kmalloc to kvmalloc is easier if the kvmalloc functions are in slab.h.
[akpm@linux-foundation.org: move the new kvrealloc() also] Link: https://lkml.kernel.org/r/20210622215757.3525604-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Randy Dunlap [Tue, 24 Aug 2021 00:00:15 +0000 (10:00 +1000)]
mm/workingset: correct kernel-doc notations
Use the documented kernel-doc format to prevent kernel-doc warnings.
mm/workingset.c:256: warning: No description found for return value of 'workingset_eviction'
mm/workingset.c:285: warning: Function parameter or member 'folio' not described in 'workingset_refault'
mm/workingset.c:285: warning: Excess function parameter 'page' description in 'workingset_refault'
Link: https://lkml.kernel.org/r/20210808203153.10678-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
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