Coly Li 1f0ffa6734 bcache: only set BCACHE_DEV_WB_RUNNING when cached device attached ... When people set a writeback percent via sysfs file, /sys/block/bcache<N>/bcache/writeback_percent current code directly sets BCACHE_DEV_WB_RUNNING to dc->disk.flags and schedules kworker dc->writeback_rate_update. If there is no cache set attached to, the writeback kernel thread is not running indeed, running dc->writeback_rate_update does not make sense and may cause NULL pointer deference when reference cache set pointer inside update_writeback_rate(). This patch checks whether the cache set point (dc->disk.c) is NULL in sysfs interface handler, and only set BCACHE_DEV_WB_RUNNING and schedule dc->writeback_rate_update when dc->disk.c is not NULL (it means the cache device is attached to a cache set). This problem might be introduced from initial bcache commit, but commit 3fd47bfe55 ("bcache: stop dc->writeback_rate_update properly") changes part of the original code piece, so I add 'Fixes: 3fd47bfe55b0' to indicate from which commit this patch can be applied. Fixes: 3fd47bfe55 ("bcache: stop dc->writeback_rate_update properly") Reported-by: Bjørn Forsman <bjorn.forsman@gmail.com> Signed-off-by: Coly Li <colyli@suse.de> Reviewed-by: Bjørn Forsman <bjorn.forsman@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>		2019-06-13 03:09:15 -06:00
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alloc.c
bcache.h
bset.c
bset.h
btree.c
btree.h
closure.c
closure.h
debug.c
debug.h
extents.c
extents.h
io.c
journal.c
journal.h
Kconfig
Makefile
movinggc.c
request.c
request.h
stats.c
stats.h
super.c
sysfs.c
sysfs.h
trace.c
util.c
util.h
writeback.c
writeback.h