bcache: register_bcache(): call blkdev_put() when cache_alloc() fails

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commit d9dc1702b2 upstream.

register_cache() is supposed to return an error string on error so that
register_bcache() will will blkdev_put and cleanup other user counters,
but it does not set 'char *err' when cache_alloc() fails (eg, due to
memory pressure) and thus register_bcache() performs no cleanup.

register_bcache() <----------\  <- no jump to err_close, no blkdev_put()
   |                         |
   +->register_cache()       |  <- fails to set char *err
         |                   |
         +->cache_alloc() ---/  <- returns error

This patch sets `char *err` for this failure case so that register_cache()
will cause register_bcache() to correctly jump to err_close and do
cleanup.  This was tested under OOM conditions that triggered the bug.

Signed-off-by: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

...

This commit is contained in:

Eric Wheeler 2016-06-17 15:01:54 -07:00 • committed by Ben Hutchings

parent c01214f730

commit ef96334100

1 changed files with 7 additions and 2 deletions

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9

drivers/md/bcache/super.c

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