4.15-stable review patch. If anyone has any objections, please let me know.
------------------ From: Florian Westphal <[email protected]> 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 <[email protected]> Bisected-by: Mike Christie <[email protected]> Tested-by: Mike Christie <[email protected]> Diagnosed-by: Nicholas Bellinger <[email protected]> Fixes: e7942d0633c4 ("tcp: remove prequeue support") Signed-off-by: Florian Westphal <[email protected]> Cc: [email protected] # 4.14+ Signed-off-by: Nicholas Bellinger <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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; }
