From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit a91b750fd6629354460282bbf5146c01b05c4859 ]
syzbot is reporting lockdep warning at rds_tcp_reset_callbacks() [1], for commit ac3615e7f3cffe2a ("RDS: TCP: Reduce code duplication in rds_tcp_reset_callbacks()") added cancel_delayed_work_sync() into a section protected by lock_sock() without realizing that rds_send_xmit() might call lock_sock().
We don't need to protect cancel_delayed_work_sync() using lock_sock(), for even if rds_{send,recv}_worker() re-queued this work while __flush_work() from cancel_delayed_work_sync() was waiting for this work to complete, retried rds_{send,recv}_worker() is no-op due to the absence of RDS_CONN_UP bit.
Link: https://syzkaller.appspot.com/bug?extid=78c55c7bc6f66e53dce2 [1] Reported-by: syzbot syzbot+78c55c7bc6f66e53dce2@syzkaller.appspotmail.com Co-developed-by: Hillf Danton hdanton@sina.com Signed-off-by: Hillf Danton hdanton@sina.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Tested-by: syzbot syzbot+78c55c7bc6f66e53dce2@syzkaller.appspotmail.com Fixes: ac3615e7f3cffe2a ("RDS: TCP: Reduce code duplication in rds_tcp_reset_callbacks()") Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/rds/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/rds/tcp.c b/net/rds/tcp.c index 5327d130c4b5..b560d06e6d96 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -166,10 +166,10 @@ void rds_tcp_reset_callbacks(struct socket *sock, */ atomic_set(&cp->cp_state, RDS_CONN_RESETTING); wait_event(cp->cp_waitq, !test_bit(RDS_IN_XMIT, &cp->cp_flags)); - lock_sock(osock->sk); /* reset receive side state for rds_tcp_data_recv() for osock */ cancel_delayed_work_sync(&cp->cp_send_w); cancel_delayed_work_sync(&cp->cp_recv_w); + lock_sock(osock->sk); if (tc->t_tinc) { rds_inc_put(&tc->t_tinc->ti_inc); tc->t_tinc = NULL;