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As a prerequisite, complement commit3d1cb2059d("workqueue: include workqueue info when printing debug dump of a worker task") to be usable with kernel modules by exporting the symbol set_worker_desc(). Current built-in user was introduced with commitef3b101925("writeback: set worker desc to identify writeback workers in task dumps"). Can help distinguishing work items which do not have adapter scope. Description is printed out with task dump for debugging on WARN, BUG, panic, or magic-sysrq [show-task-states(t)]. Example: $ echo 0 >| /sys/bus/ccw/drivers/zfcp/0.0.1880/0x50050763031bd327/failed & $ echo 't' >| /proc/sysrq-trigger $ dmesg sysrq: SysRq : Show State task PC stack pid father ... zfcp_q_0.0.1880 S14640 2165 2 0x02000000 Call Trace: ([<00000000009df464>] __schedule+0xbf4/0xc78) [<00000000009df57c>] schedule+0x94/0xc0 [<0000000000168654>] rescuer_thread+0x33c/0x3a0 [<000000000016f8be>] kthread+0x166/0x178 [<00000000009e71f2>] kernel_thread_starter+0x6/0xc [<00000000009e71ec>] kernel_thread_starter+0x0/0xc no locks held by zfcp_q_0.0.1880/2165. ... kworker/u512:2 D11280 2193 2 0x02000000 Workqueue: zfcp_q_0.0.1880 zfcp_scsi_rport_work [zfcp] (zrpd-50050763031bd327) ^^^^^^^^^^^^^^^^^^^^^ Call Trace: ([<00000000009df464>] __schedule+0xbf4/0xc78) [<00000000009df57c>] schedule+0x94/0xc0 [<00000000009e50c0>] schedule_timeout+0x488/0x4d0 [<00000000001e425c>] msleep+0x5c/0x78 >>test code only<< [<000003ff8008a21e>] zfcp_scsi_rport_work+0xbe/0x100 [zfcp] [<0000000000167154>] process_one_work+0x3b4/0x718 [<000000000016771c>] worker_thread+0x264/0x408 [<000000000016f8be>] kthread+0x166/0x178 [<00000000009e71f2>] kernel_thread_starter+0x6/0xc [<00000000009e71ec>] kernel_thread_starter+0x0/0xc 2 locks held by kworker/u512:2/2193: #0: (name){++++.+}, at: [<0000000000166f4e>] process_one_work+0x1ae/0x718 #1: ((&(&port->rport_work)->work)){+.+.+.}, at: [<0000000000166f4e>] process_one_work+0x1ae/0x718 ... ============================================= Showing busy workqueues and worker pools: workqueue zfcp_q_0.0.1880: flags=0x2000a pwq 512: cpus=0-255 flags=0x4 nice=0 active=1/1 in-flight: 2193:zfcp_scsi_rport_work [zfcp] pool 512: cpus=0-255 flags=0x4 nice=0 hung=0s workers=4 idle: 5 2354 2311 Work items with adapter scope are already identified by the workqueue name "zfcp_q_<devbusid>" and the work item function name. Signed-off-by: Steffen Maier <maier@linux.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>