From: Wu Bo wubo40@huawei.com

hulk inclusion category: bugfix bugzilla: NA CVE: NA

https://gitee.com/src-openeuler/kernel/issues/I28N9J ---------------------------

For some reason, during reboot the system, iscsi.service failed to logout all sessions. kernel will hang forever on its sd_sync_cache() logic, after issuing the SYNCHRONIZE_CACHE cmd to all still existent paths.

[ 1044.098991] reboot: Mddev shutdown finished. [ 1044.099311] reboot: Usermodehelper disable finished. [ 1050.611244] connection2:0: ping timeout of 5 secs expired, recv timeout 5, last rx 4295152378, last ping 4295153633, now 4295154944 [ 1348.599676] Call trace: [ 1348.599887] __switch_to+0xe8/0x150 [ 1348.600113] __schedule+0x33c/0xa08 [ 1348.600372] schedule+0x2c/0x88 [ 1348.600567] schedule_timeout+0x184/0x3a8 [ 1348.600820] io_schedule_timeout+0x28/0x48 [ 1348.601089] wait_for_common_io.constprop.2+0x168/0x258 [ 1348.601425] wait_for_completion_io_timeout+0x28/0x38 [ 1348.601762] blk_execute_rq+0x98/0xd8 [ 1348.602006] __scsi_execute+0xe0/0x1e8 [ 1348.602262] sd_sync_cache+0xd0/0x220 [sd_mod] [ 1348.602551] sd_shutdown+0x6c/0xf8 [sd_mod] [ 1348.602826] device_shutdown+0x13c/0x250 [ 1348.603078] kernel_restart_prepare+0x5c/0x68 [ 1348.603400] kernel_restart+0x20/0x98 [ 1348.603683] __se_sys_reboot+0x214/0x260 [ 1348.603987] __arm64_sys_reboot+0x24/0x30 [ 1348.604300] el0_svc_common+0x80/0x1b8 [ 1348.604590] el0_svc_handler+0x78/0xe0 [ 1348.604877] el0_svc+0x10/0x260

d754941225 (scsi: libiscsi: Allow sd_shutdown on bad transport) Once solved this problem. The iscsi_eh_cmd_timed_out() function add system_state judgment, and will return BLK_EH_DONE and mark the result as DID_NO_CONNECT when system_state is not SYSTEM_RUNNING, To tell upper layers that the command was handled during the transport layer error handler helper.

The scsi Mid Layer timeout handler function(scsi_times_out) will be abort the cmd if the scsi LLD timeout handler return BLK_EH_DONE. if abort cmd failed, will enter scsi EH logic.

Scsi EH will do reset target logic, if reset target failed, Will call iscsi_eh_session_reset() function to drop the session.

The iscsi_eh_session_reset function will wait for a relogin, session termination from userspace, or a recovery/replacement timeout. But at this time, the app iscsid has exited, and the session was marked as ISCSI_STATE_FAILED, So the SCSI EH process will never be scheduled back again.

PID: 9123 TASK: ffff80020c1b4d80 CPU: 3 COMMAND: "scsi_eh_2" #0 [ffff00008632bb70] __switch_to at ffff000080088738 #1 [ffff00008632bb90] __schedule at ffff000080a00480 #2 [ffff00008632bc20] schedule at ffff000080a00b58 #3 [ffff00008632bc30] iscsi_eh_session_reset at ffff000000d1ab9c [libiscsi] #4 [ffff00008632bcb0] iscsi_eh_recover_target at ffff000000d1d1fc [libiscsi] #5 [ffff00008632bd00] scsi_try_target_reset at ffff0000806f0bac #6 [ffff00008632bd30] scsi_eh_ready_devs at ffff0000806f2724 #7 [ffff00008632bde0] scsi_error_handler at ffff0000806f41d4 #8 [ffff00008632be70] kthread at ffff000080119ae0

Reported-by: Tianxiong Lu lutianxiong@huawei.com Signed-off-by: Wu Bo wubo40@huawei.com Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/scsi/libiscsi.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index ec356e035c5f..35d603db33bb 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -2441,7 +2441,17 @@ int iscsi_eh_session_reset(struct scsi_cmnd *sc)

mutex_lock(&session->eh_mutex); spin_lock_bh(&session->frwd_lock); - if (session->state == ISCSI_STATE_TERMINATE) { + + /* + * During shutdown, if session is prematurely disconnected, recovery + * won't happen and there will be hung cmds. To solve this case, all + * cmds would be enter scsi EH, but the EH path will wait for + * wait_event_interruptible() to complete until the state of the + * session is ISCSI_STATE_TERMINATE, ISCSI_STATE_LOGGED_IN or + * ISCSI_STATE_RECOVERY_FAILED. + */ + if (session->state == ISCSI_STATE_TERMINATE || + unlikely(system_state != SYSTEM_RUNNING)) { failed: ISCSI_DBG_EH(session, "failing session reset: Could not log back into "