On Mon, 2018-02-26 at 17:37 +0800, chenxiang (M) wrote: > When i have a test on kernel 4.16-rc1, find a issue: running IO on SATA disk, then disable the disk through > sysfs interface(echo 0 > /sys/class/sas_phy/phy-1:0:0/enable), IO will hang and never enter SCSI EH. The issue > appears every time. > > I add some prints on code and find that those IOs will be timeout after 30s, and they all enter > function scsi_eh_scmd_add, but only some of them can enter function scsi_eh_inc_host_failed. So it will never > enter SCSI EH. I suspect it is related to the patch ("commit 3bd6f43f5cb371" scsi: core: Ensure that the > SCSI error handler gets woken up ). Please have a check. Hello chenxiang, Had you already noticed patch "[PATCH v2] Avoid that ATA error handling can trigger a kernel hang or oops"? If not, can you apply that patch to your kernel and verify whether it fixes this behavior? See also https://www.mail-archive.com/linux-scsi@xxxxxxxxxxxxxxx/msg71189.html or https://patchwork.kernel.org/patch/10236213/. Thanks, Bart.