Re: [syzbot] Monthly trace report (Oct 2024)

[Aleksandr Nogikh]

Hi Steven,

Thanks for the analysis!

On Fri, Oct 11, 2024 at 6:00 PM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Fri, 11 Oct 2024 08:25:29 -0700
> syzbot <syzbot+list3bf21e6ac0139f8d008d@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> > Hello trace maintainers/developers,
> >
> > This is a 31-day syzbot report for the trace subsystem.
> > All related reports/information can be found at:
> > https://syzkaller.appspot.com/upstream/s/trace
> >
> > During the period, 1 new issues were detected and 0 were fixed.
> > In total, 10 issues are still open and 38 have been fixed so far.
> >
> > Some of the still happening issues:
> >
> > Ref Crashes Repro Title
> > <1> 34      Yes   INFO: task hung in blk_trace_ioctl (4)
> >                   https://syzkaller.appspot.com/bug?extid=ed812ed461471ab17a0c
>
> If you check the maintainers file, blktrace.c has:
>
> BLOCK LAYER
> M:      Jens Axboe <axboe@xxxxxxxxx>
> L:      linux-block@xxxxxxxxxxxxxxx

Judging by MAINTAINERS and ./scripts/get_maintainer.pl,
kernel/trace/blktrace.c belongs to both "BLOCK LAYER" and "TRACING".

$ ./scripts/get_maintainer.pl kernel/trace/blktrace.c
< ... >
linux-block@xxxxxxxxxxxxxxx (open list:BLOCK LAYER)
linux-kernel@xxxxxxxxxxxxxxx (open list:TRACING)


>
>
>
> > <2> 32      Yes   WARNING in bpf_get_stack_raw_tp
> >                   https://syzkaller.appspot.com/bug?extid=ce35de20ed6652f60652
>
> bpf_trace.c has:
>
> M:      Alexei Starovoitov <ast@xxxxxxxxxx>
> M:      Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> M:      Andrii Nakryiko <andrii@xxxxxxxxxx>
> R:      Martin KaFai Lau <martin.lau@xxxxxxxxx>
> R:      Eduard Zingerman <eddyz87@xxxxxxxxx>
> R:      Song Liu <song@xxxxxxxxxx>
> R:      Yonghong Song <yonghong.song@xxxxxxxxx>
> R:      John Fastabend <john.fastabend@xxxxxxxxx>
> R:      KP Singh <kpsingh@xxxxxxxxxx>
> R:      Stanislav Fomichev <sdf@xxxxxxxxxxx>
> R:      Hao Luo <haoluo@xxxxxxxxxx>
> R:      Jiri Olsa <jolsa@xxxxxxxxxx>
> L:      bpf@xxxxxxxxxxxxxxx

Same for kernel/trace/bpf_trace.c:

$ ./scripts/get_maintainer.pl kernel/trace/bpf_trace.c
< ... >
Matt Bobrowski <mattbobrowski@xxxxxxxxxx> (maintainer:BPF [SECURITY &
LSM] (Security Audit and Enforc...)
Steven Rostedt <rostedt@xxxxxxxxxxx> (maintainer:TRACING)

>
> > <3> 13      Yes   WARNING in get_probe_ref
> >                   https://syzkaller.appspot.com/bug?extid=8672dcb9d10011c0a160
> > <4> 6       Yes   INFO: task hung in blk_trace_remove (2)
> >                   https://syzkaller.appspot.com/bug?extid=2373f6be3e6de4f92562
> > <5> 4       Yes   possible deadlock in __mod_timer (4)
> >                   https://syzkaller.appspot.com/bug?extid=83a876aef81c9a485ae8
>
> None of these look like they are tracing infrastructure related.

Like get_maintainer.pl, syzbot relies on the MAINTAINERS file to
attribute bugs to the individual kernel subsystems. If several ones
are suitable, the bug is assigned several labels at once. It's now
actually the case for all open "trace" findings:

https://syzkaller.appspot.com/upstream/s/trace

(FWIW it's also possible to manually overwrite these labels and remove
specific bugs from the monthly reports).

I could make syzbot set "trace" only if there's no other good
candidate, but I wonder if that could hide the findings in the trace
infrastructure that manifested themselves in some specific traced
subsystem.

-- 
Aleksandr

>
> -- Steve
>
>
> >
> > ---
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> >
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> >
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>