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authorStefan Bader <stefan.bader@canonical.com>2015-11-29 18:44:49 -0800
committerJens Axboe <axboe@fb.com>2015-12-30 20:23:14 -0700
commit8d16ce540c94c9d366eb36fc91b7154d92d6397b (patch)
tree0fae348076b0dcd745a2ee2cadaba965bd0587e4 /drivers/md/bcache/writeback.h
parentd7076f21629f8f329bca4a44dc408d94670f49e2 (diff)
downloadlinux-8d16ce540c94c9d366eb36fc91b7154d92d6397b.tar.bz2
bcache: prevent crash on changing writeback_running
Added a safeguard in the shutdown case. At least while not being attached it is also possible to trigger a kernel bug by writing into writeback_running. This change adds the same check before trying to wake up the thread for that case. Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/md/bcache/writeback.h')
-rw-r--r--drivers/md/bcache/writeback.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index 0a9dab187b79..073a042aed24 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -63,7 +63,8 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
static inline void bch_writeback_queue(struct cached_dev *dc)
{
- wake_up_process(dc->writeback_thread);
+ if (!IS_ERR_OR_NULL(dc->writeback_thread))
+ wake_up_process(dc->writeback_thread);
}
static inline void bch_writeback_add(struct cached_dev *dc)