| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 068/342] bcache: prevent crash on changing writeback_running | Date | Tue, 01 Mar 2016 23:54:06 +0000 |
| |
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefan Bader <stefan.bader@canonical.com>
commit 8d16ce540c94c9d366eb36fc91b7154d92d6397b 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: Stefan Bader <stefan.bader@canonical.com> Cc: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/md/bcache/writeback.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/md/bcache/writeback.h +++ b/drivers/md/bcache/writeback.h @@ -63,7 +63,8 @@ static inline bool should_writeback(stru 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)
|