Commit 79eeb71c authored by Stefan Bader's avatar Stefan Bader Committed by Luis Henriques

bcache: prevent crash on changing writeback_running

commit 8d16ce54 upstream.

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: default avatarStefan Bader <stefan.bader@canonical.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 6468bfb9
......@@ -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)
......
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