Re: [syzbot] [fs?] INFO: task hung in synchronize_rcu (4)

[Martin KaFai Lau]

On 5/20/23 3:13 PM, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit:    dcbe4ea1985d Merge branch '1GbE' of git://git.kernel.org/p..
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=123ebd91280000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=f20b05fe035db814
> dashboard link: https://syzkaller.appspot.com/bug?extid=222aa26d0a5dbc2e84fe
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1495596a280000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1529326a280000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/41b9dda0e686/disk-dcbe4ea1.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/64d9bece8f89/vmlinux-dcbe4ea1.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/42429896dca0/bzImage-dcbe4ea1.xz
>
> The issue was bisected to:
>
> commit 3b5d4ddf8fe1f60082513f94bae586ac80188a03
> Author: Martin KaFai Lau <kafai@xxxxxx>
> Date:   Wed Mar 9 09:04:50 2022 +0000
>
>      bpf: net: Remove TC_AT_INGRESS_OFFSET and SKB_MONO_DELIVERY_TIME_OFFSET macro

I am afraid this bisect is incorrect. The commit removed a redundant macro and 
is a no-op change.