From: Mingzhe Zou mingzhe.zou@easystack.cn
commit 887554ab96588de2917b6c8c73e552da082e5368 upstream.
When multiple threads to check btree nodes in parallel, the main thread wait for all threads to stop or CACHE_SET_IO_DISABLE flag:
wait_event_interruptible(check_state->wait, atomic_read(&check_state->started) == 0 || test_bit(CACHE_SET_IO_DISABLE, &c->flags));
However, the bch_btree_node_read and bch_btree_node_read_done maybe call bch_cache_set_error, then the CACHE_SET_IO_DISABLE will be set. If the flag already set, the main thread return error. At the same time, maybe some threads still running and read NULL pointer, the kernel will crash.
This patch change the event wait condition, the main thread must wait for all threads to stop.
Fixes: 8e7102273f597 ("bcache: make bch_btree_check() to be multithreaded") Signed-off-by: Mingzhe Zou mingzhe.zou@easystack.cn Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Coly Li colyli@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/bcache/btree.c | 6 ++++-- drivers/md/bcache/writeback.c | 6 ++++-- 2 files changed, 8 insertions(+), 4 deletions(-)
--- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -2060,9 +2060,11 @@ int bch_btree_check(struct cache_set *c) } }
+ /* + * Must wait for all threads to stop. + */ wait_event_interruptible(check_state->wait, - atomic_read(&check_state->started) == 0 || - test_bit(CACHE_SET_IO_DISABLE, &c->flags)); + atomic_read(&check_state->started) == 0);
for (i = 0; i < check_state->total_threads; i++) { if (check_state->infos[i].result) { --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -998,9 +998,11 @@ void bch_sectors_dirty_init(struct bcach } }
+ /* + * Must wait for all threads to stop. + */ wait_event_interruptible(state->wait, - atomic_read(&state->started) == 0 || - test_bit(CACHE_SET_IO_DISABLE, &c->flags)); + atomic_read(&state->started) == 0);
out: kfree(state);