[PATCH 0/2] revert changes to zcache_do_preload()

Seth Jennings sjenning at linux.vnet.ibm.com
Thu Aug 23 15:33:09 UTC 2012


This patchset fixes a regression in 3.6 by reverting two dependent
commits that made changes to zcache_do_preload().

The commits undermine an assumption made by tmem_put() in
the cleancache path that preemption is disabled.  This change
introduces a race condition that can result in the wrong page
being returned by tmem_get(), causing assorted errors (segfaults,
apparent file corruption, etc) in userspace.

The corruption was discussed in this thread:
https://lkml.org/lkml/2012/8/17/494

Please apply this patchset to 3.6.  This problem didn't exist
in previous releases so nothing need be done for the stable trees.

Seth Jennings (2):
  Revert "staging: zcache: cleanup zcache_do_preload and
    zcache_put_page"
  Revert "staging: zcache: optimize zcache_do_preload"

 drivers/staging/zcache/zcache-main.c |   54 +++++++++++++++++++---------------
 1 file changed, 31 insertions(+), 23 deletions(-)

-- 
1.7.9.5




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