Hi, Am 23.10.2017 um 16:00 schrieb Coly Li: > 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. It seems i'm missing a5f3d8a5eaaf but i have 09b3efec81de. I missed it because git log ..linux-block/for-next -- drivers/md/bcache/ does not show it. It seems linux-block/for-next does not contain it? Which branch should i use? Only those contain the mentioned commit: remotes/linux-block/for-linus remotes/linux-block/master remotes/linux-block/wbt-odirect Greets, Stefan > > Thanks. > -- 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