iscsi-target: make sure to wake up sleeping login worker
authorFlorian Westphal <>
Fri, 19 Jan 2018 13:36:29 +0000 (14:36 +0100)
committerNicholas Bellinger <>
Wed, 24 Jan 2018 07:03:54 +0000 (23:03 -0800)
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.

(Drop WARN_ON usage - nab)

Reported-by: Mike Christie <>
Bisected-by: Mike Christie <>
Tested-by: Mike Christie <>
Diagnosed-by: Nicholas Bellinger <>
Fixes: e7942d0633c4 ("tcp: remove prequeue support")
Signed-off-by: Florian Westphal <>
Cc: # 4.14+
Signed-off-by: Nicholas Bellinger <>

index b686e2ce9c0e5df3e6142f5cf4ab144ef6d5ef85..8a5e8d17a942620d8f17bb519bbb4fffd369e494 100644 (file)
@@ -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)) {
                pr_debug("Got LOGIN_FLAGS_READ_ACTIVE=1, conn: %p >>>>\n", conn);
+               if (iscsi_target_sk_data_ready == conn->orig_data_ready)
+                       return;
+               conn->orig_data_ready(sk);