4.14-stable review patch. If anyone has any objections, please let me know.
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From: Florian Westphal fw@strlen.de
commit 1c130ae00b769a2e2df41bad3d6051ee8234b636 upstream.
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 mchristi@redhat.com Bisected-by: Mike Christie mchristi@redhat.com Tested-by: Mike Christie mchristi@redhat.com Diagnosed-by: Nicholas Bellinger nab@linux-iscsi.org Fixes: e7942d0633c4 ("tcp: remove prequeue support") Signed-off-by: Florian Westphal fw@strlen.de Cc: stable@vger.kernel.org # 4.14+ Signed-off-by: Nicholas Bellinger nab@linux-iscsi.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/target/iscsi/iscsi_target_nego.c | 3 +++ 1 file changed, 3 insertions(+)
--- 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(s 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 (iscsi_target_sk_data_ready == conn->orig_data_ready) + return; + conn->orig_data_ready(sk); return; }