commit 1c130ae00b 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: e7942d0633 ("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>
c8d0f63c15