Commit e6c9366b authored May 20, 2011 by Hugh Dickins Committed by Linus Torvalds May 20, 2011

tmpfs: fix highmem swapoff crash regression

Commit 778dd893 ("tmpfs: fix race between umount and swapoff")
forgot the new rules for strict atomic kmap nesting, causing

  WARNING: at arch/x86/mm/highmem_32.c:81

from __kunmap_atomic(), then

  BUG: unable to handle kernel paging request at fffb9000

from shmem_swp_set() when shmem_unuse_inode() is handling swapoff with
highmem in use.  My disgrace again.

See
  https://bugzilla.kernel.org/show_bug.cgi?id=35352



Reported-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 6de06f31

mm/shmem.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -916,11 +916,12 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, s
		if (size > ENTRIES_PER_PAGE)
		size = ENTRIES_PER_PAGE;
		offset = shmem_find_swp(entry, ptr, ptr+size);
		shmem_swp_unmap(ptr);
		if (offset >= 0) {
		shmem_dir_unmap(dir);
		ptr = shmem_swp_map(subdir);
		goto found;
		}
		shmem_swp_unmap(ptr);
		}
		}
		lost1:

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