Re: INFO: rcu detected stall in __perf_sw_event

[Finn Thain]

On Tue, 26 Mar 2019, syzbot wrote:

> syzbot has bisected this bug to:
> 
> commit cf85d89562f39cc7ae73de54639f1915a9195b7a
> Author: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
> Date:   Fri May 25 07:34:36 2018 +0000
> 
>    m68k/mac: Enable PDMA for PowerBook 500 series
> 

Looks like a false positive. But if you really are running syzkaller on a 
PowerBook 500, you'll want to check that you have an FPU, otherwise a CPU 
erratum will probably mess up your results.

-- 

> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1226cb8b200000
> start commit:   b0314565 Merge tag 'for_linus' of git://git.kernel.org/pub..
> git tree:       upstream
> final crash:    https://syzkaller.appspot.com/x/report.txt?x=1126cb8b200000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1626cb8b200000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8f00801d7b7c4fe6
> dashboard link: https://syzkaller.appspot.com/bug?extid=a41ac89a0712acde0e84
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1707cd2f400000
> 
> Reported-by: syzbot+a41ac89a0712acde0e84@xxxxxxxxxxxxxxxxxxxxxxxxx
> Fixes: cf85d89562f3 ("m68k/mac: Enable PDMA for PowerBook 500 series")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection