https://github.com/torvalds/linux
Revision d172b1a3bd065dd89234eac547fc62cf80681631 authored by Nadav Amit on 11 July 2022, 16:59:06 UTC, committed by akpm on 27 July 2022, 01:25:01 UTC
Commit 824ddc601adc ("userfaultfd: provide unmasked address on page-fault") was introduced to fix an old bug, in which the offset in the address of a page-fault was masked. Concerns were raised - although were never backed by actual code - that some userspace code might break because the bug has been around for quite a while. To address these concerns a new flag was introduced, and only when this flag is set by the user, userfaultfd provides the exact address of the page-fault. The commit however had a bug, and if the flag is unset, the offset was always masked based on a base-page granularity. Yet, for huge-pages, the behavior prior to the commit was that the address is masked to the huge-page granulrity. While there are no reports on real breakage, fix this issue. If the flag is unset, use the address with the masking that was done before. Link: https://lkml.kernel.org/r/20220711165906.2682-1-namit@vmware.com Fixes: 824ddc601adc ("userfaultfd: provide unmasked address on page-fault") Signed-off-by: Nadav Amit <namit@vmware.com> Reported-by: James Houghton <jthoughton@google.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Peter Xu <peterx@redhat.com> Reviewed-by: James Houghton <jthoughton@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
1 parent c80af0c
Tip revision: d172b1a3bd065dd89234eac547fc62cf80681631 authored by Nadav Amit on 11 July 2022, 16:59:06 UTC
userfaultfd: provide properly masked address for huge-pages
userfaultfd: provide properly masked address for huge-pages
Tip revision: d172b1a
File | Mode | Size |
---|---|---|
double.h | -rw-r--r-- | 6.2 KB |
op-1.h | -rw-r--r-- | 9.2 KB |
op-2.h | -rw-r--r-- | 19.7 KB |
op-4.h | -rw-r--r-- | 23.2 KB |
op-8.h | -rw-r--r-- | 3.8 KB |
op-common.h | -rw-r--r-- | 26.2 KB |
quad.h | -rw-r--r-- | 6.5 KB |
single.h | -rw-r--r-- | 3.8 KB |
soft-fp.h | -rw-r--r-- | 5.1 KB |
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