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author | Cesar Eduardo Barros <cesarb@cesarb.net> | 2011-03-23 05:03:13 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-23 17:54:22 +0300 |
commit | 2130781e2aaab66e5a9f2fdc8af35da0153f405c (patch) | |
tree | ccd654b948587a39b219f74e6cfd73ef6daa3658 /mm/vmstat.c | |
parent | 04948c7f80b9446009c1c4791bb93e79729724fb (diff) | |
download | linux-2130781e2aaab66e5a9f2fdc8af35da0153f405c.tar.xz |
sys_swapon: fix inode locking
A conflict between 52c50567d8ab ("mm: swap: unlock swapfile inode mutex
before closing file on bad swapfiles") and 83ef99befc32 ("sys_swapon:
remove did_down variable") caused a double unlock of the inode mutex
(once in bad_swap: before the filp_close, once at the end just before
returning).
The patch which added the extra unlock cleared did_down to avoid
unlocking twice, but the other patch removed the did_down variable.
To fix, set inode to NULL after the first unlock, since it will be used
after that point only for the final unlock.
While checking this patch, I found a path which could unlock without
locking, in case the same inode was added as a swapfile twice. To fix,
move the setting of the inode variable further down, to just before
claim_swapfile, which will lock the inode before doing anything else.
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmstat.c')
0 files changed, 0 insertions, 0 deletions