On 2017/10/23 下午9:16, Stefan Priebe - Profihost AG wrote: > Hi, > > Am 23.10.2017 um 15:05 schrieb Coly Li: >> On 2017/10/23 下午8:59, Stefan Priebe - Profihost AG wrote: >>> Hi Coly, >>> >>> >>> Am 23.10.2017 um 14:56 schrieb Coly Li: >>>> On 2017/10/23 下午7:42, Stefan Priebe - Profihost AG wrote: >>>>> Hello, >>>>> >>>>> i picked all bcache patches from for-next to my 4.4 kernel to test the >>>>> new controller. >>>>> >>>>> After doing so i see random kernel panics with the following trace: >>>> >>>> Hi Stefan, >>>> >>>> Thanks for the report. This is the 3rd report I see recently for NULL >>>> pointer dereference, maybe they are related (or maybe not). Is it a >>>> panic when bcache starts to run, or during heavy workload ? >>> >>> It's during heavy / normal workload. >>> >>>> If I may have chance to trigger similar oops on my server, that will be >>>> much easier. So far I cannot reproduce any oops, neither by rebooting >>>> and assemble bcache device by udev rules, nor compose bcache device and >>>> run it by bash scripts... >>> >>> Do you need the line where this happens? It should be possible to get >>> the line from the IP: [<ffffffffc04ef62e>] output? >>> >> This is very helpful. > > May be i'm too stupid but it does not print anything useful: > > # addr2line -f -e > /usr/lib/debug/lib/modules/4.4.92+534-ph/kernel/drivers/md/bcache/bcache.ko > ffffffffc04ef62e closure_sub > ?? > ??:0 > bch_inc_gen > ??:? > >> Is it possible to get a kdump crash for the kernel >> oops, that will be much more informative :-) > > no idea how to archieve this for a remote Server. Hi Stefan, In code path of closure_wake_up(), I remember there are two patches in last run, - commit a5f3d8a5eaaf ("bcache: use llist_for_each_entry_safe() in __closure_wake_up()") - commit 09b3efec81de ("bcache: Don't reinvent the wheel but use existing llist API") Can you check whether you have all of these patches ? Or can we try to revoke these two patches and see whether oops still happens. Thanks. -- Coly Li -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html