diff options
| author | Jann Horn <jannh@google.com> | 2020-10-15 20:07:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-16 11:11:17 -0700 |
| commit | c9682d10271e1025ebfbb1675c7afffbef5c6856 (patch) | |
| tree | 6f203c4e411b658fdadeab493e4b51311bfa0d6d | |
| parent | 295a17302348bc38704ef0f11ca2ce4ce58db2e9 (diff) | |
mm/mmu_notifier: fix mmget() assert in __mmu_interval_notifier_insert
The comment talks about having to hold mmget() (which means mm_users), but
the actual check is on mm_count (which would be mmgrab()).
Given that MMU notifiers are torn down in mmput() -> __mmput() ->
exit_mmap() -> mmu_notifier_release(), I believe that the comment is
correct and the check should be on mm->mm_users. Fix it up accordingly.
Fixes: 99cb252f5e68 ("mm/mmu_notifier: add an interval tree notifier")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christian König <christian.koenig@amd.com
Link: https://lkml.kernel.org/r/20200901000143.207585-1-jannh@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/mmu_notifier.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 4fc918163dd3..5654dd19addc 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -913,7 +913,7 @@ static int __mmu_interval_notifier_insert( return -EOVERFLOW; /* Must call with a mmget() held */ - if (WARN_ON(atomic_read(&mm->mm_count) <= 0)) + if (WARN_ON(atomic_read(&mm->mm_users) <= 0)) return -EINVAL; /* pairs with mmdrop in mmu_interval_notifier_remove() */ |