linux-kernel - [syzbot] [io-uring?] KCSAN: data-race in io_wq_activate_free_worker / io_wq_worker

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Message-ID: <000000000000fc6ba706053be013@google.com>
Date:   Wed, 13 Sep 2023 04:29:56 -0700
From:   syzbot <syzbot+a36975231499dc24df44@...kaller.appspotmail.com>
To:     asml.silence@...il.com, axboe@...nel.dk, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [io-uring?] KCSAN: data-race in io_wq_activate_free_worker / io_wq_worker_running

Hello,

syzbot found the following issue on:

HEAD commit:    f97e18a3f2fb Merge tag 'gpio-updates-for-v6.6' of git://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12864667a80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fe440f256d065d3b
dashboard link: https://syzkaller.appspot.com/bug?extid=a36975231499dc24df44
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b1781aaff038/disk-f97e18a3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5b915468fd6d/vmlinux-f97e18a3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/abc8ece931f3/bzImage-f97e18a3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a36975231499dc24df44@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in io_wq_activate_free_worker / io_wq_worker_running

write to 0xffff888127f736c4 of 4 bytes by task 4731 on cpu 1:
 io_wq_worker_running+0x64/0xa0 io_uring/io-wq.c:668
 schedule_timeout+0xcc/0x230 kernel/time/timer.c:2167
 io_wq_worker+0x4b2/0x840 io_uring/io-wq.c:633
 ret_from_fork+0x2e/0x40 arch/x86/kernel/process.c:145
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

read to 0xffff888127f736c4 of 4 bytes by task 4719 on cpu 0:
 io_wq_get_acct io_uring/io-wq.c:168 [inline]
 io_wq_activate_free_worker+0xfa/0x280 io_uring/io-wq.c:267
 io_wq_enqueue+0x262/0x450 io_uring/io-wq.c:914
 io_queue_iowq+0x1d1/0x310 io_uring/io_uring.c:514
 io_queue_sqe_fallback+0x82/0xe0 io_uring/io_uring.c:2084
 io_submit_sqe io_uring/io_uring.c:2305 [inline]
 io_submit_sqes+0xbd3/0xfb0 io_uring/io_uring.c:2420
 __do_sys_io_uring_enter io_uring/io_uring.c:3628 [inline]
 __se_sys_io_uring_enter+0x1f8/0x1c10 io_uring/io_uring.c:3562
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3562
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000d -> 0x0000000b

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4719 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-01810-gf97e18a3f2fb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
==================================================================


---
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