The patch titled
Subject: userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
has been removed from the -mm tree. Its filename was
userfaultfd-check-vm_maywrite-was-set-after-verifying-the-uffd-is-registered.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Subject: userfaultfd: check VM_MAYWRITE was set after verifying the uffd is registered
Calling UFFDIO_UNREGISTER on virtual ranges not yet registered in uffd
could trigger an harmless false positive WARN_ON. Check the vma is
already registered before checking VM_MAYWRITE to shut off the false
positive warning.
Link: http://lkml.kernel.org/r/20181206212028.18726-2-aarcange@xxxxxxxxxx
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 29ec90660d68 ("userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas")
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reported-by: syzbot+06c7092e7d71218a2c16@xxxxxxxxxxxxxxxxxxxxxxxxx
Acked-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/userfaultfd.c~userfaultfd-check-vm_maywrite-was-set-after-verifying-the-uffd-is-registered
+++ a/fs/userfaultfd.c
@@ -1566,7 +1566,6 @@ static int userfaultfd_unregister(struct
cond_resched();
BUG_ON(!vma_can_userfault(vma));
- WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
/*
* Nothing to do: this vma is already registered into this
@@ -1575,6 +1574,8 @@ static int userfaultfd_unregister(struct
if (!vma->vm_userfaultfd_ctx.ctx)
goto skip;
+ WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
+
if (vma->vm_start > start)
start = vma->vm_start;
vma_end = min(end, vma->vm_end);
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
