On 2018/3/22 3:56, Bart Van Assche wrote: > On Wed, 2018-03-21 at 01:54 +0000, Chongyun Wu wrote: >> Is there any special operation or conditions to reproduce the dead lock? >> I have use SCSI sysfs delete atrribute to remove stale devices in my >> previous patch and test many times, but I haven't encountered any >> deadlock problems. > > Hello Chongyun, > > In my tests I enabled the lock validator (CONFIG_LOCKDEP) in order not only > to obtain detailed information about the cause of actual deadlocks but also > to obtain information about potential deadlocks. > > I'm not sure how to make it more likely to trigger this deadlock. But I think > that you should be aware that some SCSI transports remove the SCSI host if a > transport failure is detected and other SCSI transports don't remove the SCSI > host upon a transport failure. I ran my tests with the SRP protocol and the > SRP transport protocol removes the SCSI host if a transport failure persists > long enough. Maybe triggering SCSI host removal often helps to trigger that > deadlock. > > Bart. > > > Hi Bart, Thanks, as you mentioned maybe we have different scsi transport so we haven't found deadlock so far. Hope your mentioned issue *Avoid that SCSI device removal through sysfs triggers a deadlock* can be resolved by root. We often encounter problems with device residual which cause some issues and want to find a safe and effective method to clean up it. Regards, Chongyun -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
