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| author |   Mingzhe Zou <mingzhe.zou@easystack.cn> | 2022-02-11 14:39:15 +0800 |
|---|---|---|
| committer |   Coly Li <colyli@suse.de> | 2022-03-06 22:33:45 +0800 |
| commit | 887554ab96588de2917b6c8c73e552da082e5368 (patch) | |
| tree | 0570e2ced54a9570d4d179770b14ce9a206646cf | |
| parent | bcache: fixup bcache_dev_sectors_dirty_add() multithreaded CPU false sharing (diff) | |
| download | linux-dev-887554ab96588de2917b6c8c73e552da082e5368.tar.xz linux-dev-887554ab96588de2917b6c8c73e552da082e5368.zip | |
bcache: fixup multiple threads crash
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>
| -rw-r--r-- | drivers/md/bcache/btree.c | 6 | ||||
| -rw-r--r-- | drivers/md/bcache/writeback.c | 6 |
2 files changed, 8 insertions, 4 deletions
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c index 88c573eeb598..ad9f16689419 100644 --- 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) { diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c index 176461f89f46..9ee0005874cd 100644 --- a/drivers/md/bcache/writeback.c +++ b/drivers/md/bcache/writeback.c @@ -1001,9 +1001,11 @@ void bch_sectors_dirty_init(struct bcache_device *d) } } + /* + * 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); |