Revision - 33313a7 - mm: lock newly mapped VMA which can be modified after it becomes [...] - origin: https://github.com/torvalds/linux

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17 August 2024, 15:42:30 UTC

Revision 33313a747e81af9f31d0d45de78c9397fa3655eb authored by Suren Baghdasaryan on 08 July 2023, 19:12:11 UTC, committed by Linus Torvalds on 08 July 2023, 21:08:02 UTC

mm: lock newly mapped VMA which can be modified after it becomes visible

mmap_region adds a newly created VMA into VMA tree and might modify it
afterwards before dropping the mmap_lock.  This poses a problem for page
faults handled under per-VMA locks because they don't take the mmap_lock
and can stumble on this VMA while it's still being modified.  Currently
this does not pose a problem since post-addition modifications are done
only for file-backed VMAs, which are not handled under per-VMA lock.
However, once support for handling file-backed page faults with per-VMA
locks is added, this will become a race.

Fix this by write-locking the VMA before inserting it into the VMA tree.
Other places where a new VMA is added into VMA tree do not modify it
after the insertion, so do not need the same locking.

Cc: stable@vger.kernel.org
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Tip revision: 33313a747e81af9f31d0d45de78c9397fa3655eb authored by Suren Baghdasaryan on 08 July 2023, 19:12:11 UTC
mm: lock newly mapped VMA which can be modified after it becomes visible

Tip revision: 33313a7

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.clang-format	-rw-r--r--	20.1 KB
.cocciconfig	-rw-r--r--	59 bytes
.get_maintainer.ignore	-rw-r--r--	151 bytes
.gitattributes	-rw-r--r--	105 bytes
.gitignore	-rw-r--r--	2.0 KB
.mailmap	-rw-r--r--	28.4 KB
.rustfmt.toml	-rw-r--r--	369 bytes
COPYING	-rw-r--r--	496 bytes
CREDITS	-rw-r--r--	100.3 KB
Kbuild	-rw-r--r--	2.5 KB
Kconfig	-rw-r--r--	555 bytes
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Makefile	-rw-r--r--	69.8 KB
README	-rw-r--r--	727 bytes

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mm: lock newly mapped VMA which can be modified after it becomes visible

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