Re: [syzbot] [mm?] INFO: rcu detected stall in sys_umount (3)

[Hillf Danton]

On Mon, 18 Aug 2025 19:26:16 +0100 Al Viro wrote:
> On Mon, Aug 18, 2025 at 02:42:28AM -0700, syzbot wrote:
> > syzbot has found a reproducer for the following issue on:
> > 
> > HEAD commit:    8f5ae30d69d7 Linux 6.17-rc1
> > git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1321eba2580000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=8c5ac3d8b8abfcb
> > dashboard link: https://syzkaller.appspot.com/bug?extid=1ec0f904ba50d06110b1
> > compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> > userspace arch: arm64
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10cba442580000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10a1eba2580000
> > 
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/18a2e4bd0c4a/disk-8f5ae30d.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/3b5395881b25/vmlinux-8f5ae30d.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/e875f4e3b7ff/Image-8f5ae30d.gz.xz
> > mounted in repro: https://storage.googleapis.com/syzbot-assets/43186d9e448c/mount_0.gz
> >   fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=174ba442580000)
> > 
> > The issue was bisected to:
> > 
> > commit d15121be7485655129101f3960ae6add40204463
> > Author: Paolo Abeni <pabeni@xxxxxxxxxx>
> > Date:   Mon May 8 06:17:44 2023 +0000
> > 
> >     Revert "softirq: Let ksoftirqd do its job"
> 
> Would be interesting to see how it behaves on 

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git  fixes