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| author | Andrea Arcangeli <aarcange@redhat.com> | 2017-08-10 15:23:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-08-10 15:54:06 -0700 |
| commit | 5af10dfd0afc559bb4b0f7e3e8227a1578333995 (patch) | |
| tree | 9885cfee8db94efb40a23f28dddacd5dd4370a5f /mm/hugetlb.c | |
| parent | 75dddef32514f7aa58930bde6a1263253bc3d4ba (diff) | |
| download | lwn-5af10dfd0afc559bb4b0f7e3e8227a1578333995.tar.gz lwn-5af10dfd0afc559bb4b0f7e3e8227a1578333995.zip | |
userfaultfd: hugetlbfs: remove superfluous page unlock in VM_SHARED case
huge_add_to_page_cache->add_to_page_cache implicitly unlocks the page
before returning in case of errors.
The error returned was -EEXIST by running UFFDIO_COPY on a non-hole
offset of a VM_SHARED hugetlbfs mapping. It was an userland bug that
triggered it and the kernel must cope with it returning -EEXIST from
ioctl(UFFDIO_COPY) as expected.
page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
kernel BUG at mm/filemap.c:964!
invalid opcode: 0000 [#1] SMP
CPU: 1 PID: 22582 Comm: qemu-system-x86 Not tainted 4.11.11-300.fc26.x86_64 #1
RIP: unlock_page+0x4a/0x50
Call Trace:
hugetlb_mcopy_atomic_pte+0xc0/0x320
mcopy_atomic+0x96f/0xbe0
userfaultfd_ioctl+0x218/0xe90
do_vfs_ioctl+0xa5/0x600
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x1a/0xa9
Link: http://lkml.kernel.org/r/20170802165145.22628-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index a1a0ac0ad6f6..31e207cb399b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4062,9 +4062,9 @@ out: return ret; out_release_unlock: spin_unlock(ptl); -out_release_nounlock: if (vm_shared) unlock_page(page); +out_release_nounlock: put_page(page); goto out; } |