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635f6b0893
When a cxlflash adapter goes into EEH recovery and multiple processes (each having established its own context) are active, the EEH recovery can hang if the processes attempt to recover in parallel. The symptom logged after a couple of minutes is: INFO: task eehd:48 blocked for more than 120 seconds. Not tainted 4.5.0-491-26f710d+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. eehd 0 48 2 Call Trace: __switch_to+0x2f0/0x410 __schedule+0x300/0x980 schedule+0x48/0xc0 rwsem_down_write_failed+0x294/0x410 down_write+0x88/0xb0 cxlflash_pci_error_detected+0x100/0x1c0 [cxlflash] cxl_vphb_error_detected+0x88/0x110 [cxl] cxl_pci_error_detected+0xb0/0x1d0 [cxl] eeh_report_error+0xbc/0x130 eeh_pe_dev_traverse+0x94/0x160 eeh_handle_normal_event+0x17c/0x450 eeh_handle_event+0x184/0x370 eeh_event_handler+0x1c8/0x1d0 kthread+0x110/0x130 ret_from_kernel_thread+0x5c/0xa4 INFO: task blockio:33215 blocked for more than 120 seconds. Not tainted 4.5.0-491-26f710d+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. blockio 0 33215 33213 Call Trace: 0x1 (unreliable) __switch_to+0x2f0/0x410 __schedule+0x300/0x980 schedule+0x48/0xc0 rwsem_down_read_failed+0x124/0x1d0 down_read+0x68/0x80 cxlflash_ioctl+0x70/0x6f0 [cxlflash] scsi_ioctl+0x3b0/0x4c0 sg_ioctl+0x960/0x1010 do_vfs_ioctl+0xd8/0x8c0 SyS_ioctl+0xd4/0xf0 system_call+0x38/0xb4 INFO: task eehd:48 blocked for more than 120 seconds. The hang is because of a 3 way dead-lock: Process A holds the recovery mutex, and waits for eehd to complete. Process B holds the semaphore and waits for the recovery mutex. eehd waits for semaphore. The fix is to have Process B above release the semaphore before attempting to acquire the recovery mutex. This will allow eehd to proceed to completion. Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com> Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> |
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| .. | ||
| common.h | ||
| Kconfig | ||
| lunmgt.c | ||
| main.c | ||
| main.h | ||
| Makefile | ||
| sislite.h | ||
| superpipe.c | ||
| superpipe.h | ||
| vlun.c | ||
| vlun.h | ||