syzbot


possible deadlock in io_worker_cancel_cb
Status: upstream: reported C repro on 2021/12/13 06:08
Reported-by: syzbot+b18b8be69df33a3918e9@syzkaller.appspotmail.com
Fix commit: d800c65c2d4e io-wq: drop wqe lock before creating new worker
Patched on: [ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-riscv64 ci-upstream-kmsan-gce ci-upstream-kmsan-gce-386]
First crash: 46d, last: 41d

Cause bisection: introduced by (bisect log) :
commit 71a85387546e50b1a37b0fa45dadcae3bfb35cf6
Author: Jens Axboe <axboe@kernel.dk>
Date: Fri Dec 10 15:29:30 2021 +0000

  io-wq: check for wq exit after adding new worker task_work

Crash: possible deadlock in io_worker_cancel_cb (log)
Repro: C syz .config
Patch testing requests:
Created Duration User Patch Repo Result
2021/12/13 16:06 12m axboe@kernel.dk git://git.kernel.dk/linux-block io_uring-5.16 OK

Sample crash report:

Crashes (9):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2021/12/12 10:36 upstream a763d5a5abd6 49ca1f59 .config log report syz C possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce-root 2021/12/17 14:53 upstream fa36bbe6d43f 44068e19 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce 2021/12/17 07:45 upstream fa36bbe6d43f 44068e19 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce-smack-root 2021/12/16 19:42 upstream fa36bbe6d43f 8dd6a5e3 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce 2021/12/15 06:50 upstream 5472f14a3742 f752fb53 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce-root 2021/12/14 13:31 upstream 5472f14a3742 d018dd31 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce 2021/12/12 19:27 upstream a763d5a5abd6 49ca1f59 .config log report info possible deadlock in io_worker_cancel_cb
ci-upstream-kasan-gce-smack-root 2021/12/12 07:28 upstream a763d5a5abd6 49ca1f59 .config log report info possible deadlock in io_worker_cancel_cb
ci-qemu-upstream-386 2021/12/16 21:20 upstream fa36bbe6d43f 8dd6a5e3 .config log report info possible deadlock in io_worker_cancel_cb