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authorMingzhe Zou <mingzhe.zou@easystack.cn>2022-02-11 09:39:15 +0300
committerColy Li <colyli@suse.de>2022-03-06 17:33:45 +0300
commit887554ab96588de2917b6c8c73e552da082e5368 (patch)
tree0570e2ced54a9570d4d179770b14ce9a206646cf /drivers/md/bcache
parent7b1002f7cfe581930f63787a0b3de0144e61ed55 (diff)
downloadlinux-887554ab96588de2917b6c8c73e552da082e5368.tar.xz
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>
Diffstat (limited to 'drivers/md/bcache')
-rw-r--r--drivers/md/bcache/btree.c6
-rw-r--r--drivers/md/bcache/writeback.c6
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);