https://github.com/torvalds/linux
Revision cb185d5f1ebf900f4ae3bf84cee212e6dd035aca authored by Nadav Amit on 18 October 2021, 22:15:25 UTC, committed by Linus Torvalds on 19 October 2021, 06:22:02 UTC
A race is possible when a process exits, its VMAs are removed by
exit_mmap() and at the same time userfaultfd_writeprotect() is called.
The race was detected by KASAN on a development kernel, but it appears
to be possible on vanilla kernels as well.
Use mmget_not_zero() to prevent the race as done in other userfaultfd
operations.
Link: https://lkml.kernel.org/r/20210921200247.25749-1-namit@vmware.com
Fixes: 63b2d4174c4ad ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl")
Signed-off-by: Nadav Amit <namit@vmware.com>
Tested-by: Li Wang <liwang@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 8913970
Tip revision: cb185d5f1ebf900f4ae3bf84cee212e6dd035aca authored by Nadav Amit on 18 October 2021, 22:15:25 UTC
userfaultfd: fix a race between writeprotect and exit_mmap()
userfaultfd: fix a race between writeprotect and exit_mmap()
Tip revision: cb185d5
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| include | ||
| init | ||
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| lib | ||
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| net | ||
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| .clang-format | -rw-r--r-- | 16.6 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 71 bytes |
| .gitattributes | -rw-r--r-- | 62 bytes |
| .gitignore | -rw-r--r-- | 1.9 KB |
| .mailmap | -rw-r--r-- | 19.8 KB |
| COPYING | -rw-r--r-- | 496 bytes |
| CREDITS | -rw-r--r-- | 98.6 KB |
| Kbuild | -rw-r--r-- | 1.3 KB |
| Kconfig | -rw-r--r-- | 555 bytes |
| MAINTAINERS | -rw-r--r-- | 605.7 KB |
| Makefile | -rw-r--r-- | 64.0 KB |
| README | -rw-r--r-- | 727 bytes |
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