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authorAndrea Arcangeli <aarcange@redhat.com>2017-08-10 15:23:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-10 15:54:06 -0700
commit5af10dfd0afc559bb4b0f7e3e8227a1578333995 (patch)
tree9885cfee8db94efb40a23f28dddacd5dd4370a5f
parent75dddef32514f7aa58930bde6a1263253bc3d4ba (diff)
downloadlinux-stericsson-5af10dfd0afc559bb4b0f7e3e8227a1578333995.tar.gz
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>
-rw-r--r--mm/hugetlb.c2
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;
}