Mike Christie reports:
Starting in 4.14 iscsi logins will fail around 50% of the time.
Problem appears to be that iscsi_target_sk_data_ready() callback may
return without doing anything in case it finds the login work queue
is still blocked in sock_recvmsg().
Nicholas Bellinger says:
It would indicate users providing their own ->sk_data_ready() callback
must be responsible for waking up a kthread context blocked on
sock_recvmsg(..., MSG_WAITALL), when a second ->sk_data_ready() is
received before the first sock_recvmsg(..., MSG_WAITALL) completes.
So, do this and invoke the original data_ready() callback -- in
case of tcp sockets this takes care of waking the thread.
Disclaimer: I do not understand why this problem did not show up before
tcp prequeue removal.
Reported-by: Mike Christie <mchristi@xxxxxxxxxx>
Bisected-by: Mike Christie <mchristi@xxxxxxxxxx>
Tested-by: Mike Christie <mchristi@xxxxxxxxxx>
Diagnosed-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Fixes: e7942d0633c4 ("tcp: remove prequeue support")
Signed-off-by: Florian Westphal <fw@xxxxxxxxx>
---
drivers/target/iscsi/iscsi_target_nego.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index b686e2ce9c0e..3723f8f419aa 100644
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -432,6 +432,9 @@ static void iscsi_target_sk_data_ready(struct sock *sk)
if (test_and_set_bit(LOGIN_FLAGS_READ_ACTIVE, &conn->login_flags)) {
write_unlock_bh(&sk->sk_callback_lock);
pr_debug("Got LOGIN_FLAGS_READ_ACTIVE=1, conn: %p >>>>\n", conn);
+ if (WARN_ON(iscsi_target_sk_data_ready == conn->orig_data_ready))
+ return;
+ conn->orig_data_ready(sk);
return;
}
--
2.13.6
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