tree 39402a2d467a856d0f956015a7ad0772719bf1b6
parent ac7ac9f2b9bfd9b68a1571d27e4c8bebb4788914
author Nicolas Pitre <nico@cam.org> 1252124737 -0400
committer Linus Torvalds <torvalds@linux-foundation.org> 1252183268 -0700

ext2: fix unbalanced kmap()/kunmap()

In ext2_rename(), dir_page is acquired through ext2_dotdot().  It is
then released through ext2_set_link() but only if old_dir != new_dir.
Failing that, the pkmap reference count is never decremented and the
page remains pinned forever.  Repeat that a couple times with highmem
pages and all pkmap slots get exhausted, and every further kmap() calls
end up stalling on the pkmap_map_wait queue at which point the whole
system comes to a halt.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>