On 3/28/18 9:13 PM, Zephaniah E. Loss-Cutler-Hull wrote: > On 03/28/2018 06:02 PM, Jens Axboe wrote: >> On 3/28/18 5:03 PM, Zephaniah E. Loss-Cutler-Hull wrote: >>> I am not subscribed to any of the lists on the To list here, please CC >>> me on any replies. >>> >>> I am encountering a fairly consistent crash anywhere from 15 minutes to >>> 12 hours after boot with scsi_mod.use_blk_mq=1 dm_mod.use_blk_mq=1> >>> The crash looks like: >>> > >>> >>> Looking through the code, I'd guess that this is dying inside >>> blkg_rwstat_add, which calls percpu_counter_add_batch, which is what RIP >>> is pointing at. >> >> Leaving the whole thing here for Paolo - it's crashing off insertion of >> a request coming out of SG_IO. Don't think we've seen this BFQ failure >> case before. >> >> You can mitigate this by switching the scsi-mq devices to mq-deadline >> instead. >> > > I'm thinking that I should also be able to mitigate it by disabling > CONFIG_DEBUG_BLK_CGROUP. > > That should remove that entire chunk of code. > > Of course, that won't help if this is actually a symptom of a bigger > problem. Yes, it's not a given that it will fully mask the issue at hand. But turning off BFQ has a much higher chance of working for you. This time actually CC'ing Paolo. -- Jens Axboe
