If the transaction chose itself as a victim before and restarted, it might request a no fail lock request this time. But it might be added to others' lock graph and be chose as the victim again, it's no longer safe without additional check. We can also convert the cycle detector to be fully RCU-based to solve that unsoundness, but the latency added to trans_put and additional memory required may not worth it.
Signed-off-by: Alan Huang <[email protected]> --- fs/bcachefs/btree_locking.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/bcachefs/btree_locking.c b/fs/bcachefs/btree_locking.c index bf25fd0a1cca..fff176382e30 100644 --- a/fs/bcachefs/btree_locking.c +++ b/fs/bcachefs/btree_locking.c @@ -293,7 +293,7 @@ int bch2_check_for_deadlock(struct btree_trans *trans, struct printbuf *cycle) g.nr = 0; - if (trans->lock_must_abort) { + if (trans->lock_must_abort && !trans->lock_may_not_fail) { if (cycle) return -1; -- 2.45.2
