From 105fa2f44e504c830697b0c794822112d79808dc Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Sat, 3 Jun 2017 05:35:47 -0700 Subject: [PATCH] iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP This patch fixes a BUG() in iscsit_close_session() that could be triggered when iscsit_logout_post_handler() execution from within tx thread context was not run for more than SECONDS_FOR_LOGOUT_COMP (15 seconds), and the TCP connection didn't already close before then forcing tx thread context to automatically exit. This would manifest itself during explicit logout as: [33206.974254] 1 connection(s) still exist for iSCSI session to iqn.1993-08.org.debian:01:3f5523242179 [33206.980184] INFO: NMI handler (kgdb_nmi_handler) took too long to run: 2100.772 msecs [33209.078643] ------------[ cut here ]------------ [33209.078646] kernel BUG at drivers/target/iscsi/iscsi_target.c:4346! Normally when explicit logout attempt fails, the tx thread context exits and iscsit_close_connection() from rx thread context does the extra cleanup once it detects conn->conn_logout_remove has not been cleared by the logout type specific post handlers. To address this special case, if the logout post handler in tx thread context detects conn->tx_thread_active has already been cleared, simply return and exit in order for existing iscsit_close_connection() logic from rx thread context do failed logout cleanup. Reported-by: Bart Van Assche Tested-by: Bart Van Assche Cc: Mike Christie Cc: Hannes Reinecke Cc: Sagi Grimberg Cc: stable@vger.kernel.org # 3.14+ Tested-by: Gary Guo Tested-by: Chu Yuan Lin Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 0d8f81591bed..c0254516b380 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4423,8 +4423,11 @@ static void iscsit_logout_post_handler_closesession( * always sleep waiting for RX/TX thread shutdown to complete * within iscsit_close_connection(). */ - if (!conn->conn_transport->rdma_shutdown) + if (!conn->conn_transport->rdma_shutdown) { sleep = cmpxchg(&conn->tx_thread_active, true, false); + if (!sleep) + return; + } atomic_set(&conn->conn_logout_remove, 0); complete(&conn->conn_logout_comp); @@ -4440,8 +4443,11 @@ static void iscsit_logout_post_handler_samecid( { int sleep = 1; - if (!conn->conn_transport->rdma_shutdown) + if (!conn->conn_transport->rdma_shutdown) { sleep = cmpxchg(&conn->tx_thread_active, true, false); + if (!sleep) + return; + } atomic_set(&conn->conn_logout_remove, 0); complete(&conn->conn_logout_comp); -- 2.20.1