On Wed, Jul 8, 2020 at 12:07 PM Guenter Roeck <li...@roeck-us.net> wrote: > > On 7/8/20 11:34 AM, Cong Wang wrote: > > Hi, > > > > On Wed, Jul 8, 2020 at 8:33 AM Guenter Roeck <li...@roeck-us.net> wrote: > >> This patch causes all my s390 boot tests to crash. Reverting it fixes > >> the problem. Please see bisect results and and crash log below. > >> > > ... > >> Crash log: > > > > Interesting. I don't see how unix socket is any special here, it creates > > a peer sock with sk_alloc(), but this is not any different from two > > separated > > sockets. > > > > What is your kernel config? Do you enable CONFIG_CGROUP_NET_PRIO > > or CONFIG_CGROUP_NET_CLASSID? I can see there might be a problem > > if you don't enable either of them but enable CONFIG_CGROUP_BPF. > > > > cgroup specific configuration bits: > > CONFIG_CGROUPS=y > CONFIG_BLK_CGROUP=y > CONFIG_CGROUP_WRITEBACK=y > CONFIG_CGROUP_SCHED=y > CONFIG_CGROUP_PIDS=y > CONFIG_CGROUP_RDMA=y > CONFIG_CGROUP_FREEZER=y > CONFIG_CGROUP_HUGETLB=y > CONFIG_CGROUP_DEVICE=y > CONFIG_CGROUP_CPUACCT=y > CONFIG_CGROUP_PERF=y > CONFIG_CGROUP_BPF=y > # CONFIG_CGROUP_DEBUG is not set > CONFIG_SOCK_CGROUP_DATA=y > CONFIG_BLK_CGROUP_RWSTAT=y > CONFIG_BLK_CGROUP_IOLATENCY=y > CONFIG_BLK_CGROUP_IOCOST=y > # CONFIG_BFQ_CGROUP_DEBUG is not set > # CONFIG_NETFILTER_XT_MATCH_CGROUP is not set > CONFIG_NET_CLS_CGROUP=y > CONFIG_CGROUP_NET_PRIO=y > CONFIG_CGROUP_NET_CLASSID=y > > This originates from arch/s390/configs/defconfig; I don't touch > any cgroup specific configuration in my tests.
Good to know you enable everything related here. > > > And if you have the full kernel log, it would be helpful too. > > > > https://kerneltests.org/builders/qemu-s390-pending-fixes/builds/222/steps/qemubuildcommand/logs/stdio It looks like cgroup_sk_alloc_disabled is always false in your case. This makes the bug even more weird. Unless there is a refcnt bug prior to my commit, I don't see how it could happen. > > Interestingly, enabling CONFIG_BFQ_CGROUP_DEBUG makes the problem disappear. Yeah, I guess there might be some cgroup refcnt bug which could just paper out with CONFIG_BFQ_CGROUP_DEBUG=y. If you can test patches, I can send you a debugging patch for you to collect more data. I assume this is 100% reproducible on your side? Thanks.
