On Thu, Oct 27, 2022 at 07:45:16PM +0800, Hao Sun wrote: > Jiri Olsa <olsajiri@xxxxxxxxx> 于2022年10月27日周四 19:24写道： > > > > On Thu, Oct 27, 2022 at 10:27:28AM +0800, Hao Sun wrote: > > > Hi, > > > > > > The following warning can be triggered with the C reproducer in the link. > > > Syzbot also reported this several days ago, Jiri posted a patch that > > > uses bpf prog `active` field to fix this by 05b24ff9b2cfab (bpf: > > > Prevent bpf program recursion...) according to syzbot dashboard > > > (https://syzkaller.appspot.com/bug?id=179313fb375161d50a98311a28b8e2fc5f7350f9). > > > But this warning can still be triggered on 247f34f7b803 > > > (Linux-v6.1-rc2) that already merged the patch, so it seems that this > > > still is an issue. > > > > > > HEAD commit: 247f34f7b803 Linux 6.1-rc2 > > > git tree: upstream > > > console output: https://pastebin.com/raw/kNw8JCu5 > > > kernel config: https://pastebin.com/raw/sE5QK5HL > > > C reproducer: https://pastebin.com/raw/X96ASi27 > > > > hi, > > right, that fix addressed that issue for single bpf program, > > and it won't prevent if there are multiple programs hook on > > contention_begin tracepoint and calling bpf_trace_printk, > > > > I'm not sure we can do something there.. will check > > > > do you run just the reproducer, or you load the server somehow? > > I cannot hit the issue so far > > > > Hi, > > Last email has format issues, resend it here. > > I built the kernel with the config in the link, which contains > “CONFIG_CMDLINE="earlyprintk=serial net.ifnames=0 > sysctl.kernel.hung_task_all_cpu_backtrace=1 panic_on_warn=1 …”, and > boot the kernel with normal qemu setup and then the warning can be > triggered by executing the reproducer. > > Also, I’m willing to test the proposed patch if any. fyi I reproduced that.. will check if we can do anything about that thanks, jirka
