On 8/5/24 12:53 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: a5dbd76a8942 Merge tag 'x86-urgent-2024-08-04' of git://gi.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=13d5a373980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=d16924117a4f7e9 > dashboard link: https://syzkaller.appspot.com/bug?extid=b3e4f2f51ed645fd5df2 > 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/ba663ad5dbf5/disk-a5dbd76a.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/226a427d6581/vmlinux-a5dbd76a.xz > kernel image: https://storage.googleapis.com/syzbot-assets/9f982777516a/bzImage-a5dbd76a.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+b3e4f2f51ed645fd5df2@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KCSAN: data-race in __flush_work / __flush_work > > write to 0xffff8881223aa3e8 of 8 bytes by task 3998 on cpu 0: > instrument_write include/linux/instrumented.h:41 [inline] > ___set_bit include/asm-generic/bitops/instrumented-non-atomic.h:28 [inline] > insert_wq_barrier kernel/workqueue.c:3790 [inline] > start_flush_work kernel/workqueue.c:4142 [inline] > __flush_work+0x30b/0x570 kernel/workqueue.c:4178 > flush_work kernel/workqueue.c:4229 [inline] > flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251 > io_fallback_tw+0x24b/0x320 io_uring/io_uring.c:1087 > tctx_task_work_run+0xd1/0x1b0 io_uring/io_uring.c:1099 > tctx_task_work+0x40/0x80 io_uring/io_uring.c:1124 > task_work_run+0x13a/0x1a0 kernel/task_work.c:228 > exit_task_work include/linux/task_work.h:40 [inline] > do_exit+0x5dd/0x1720 kernel/exit.c:882 > do_group_exit+0x102/0x150 kernel/exit.c:1031 > get_signal+0xf2f/0x1080 kernel/signal.c:2917 > arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310 > exit_to_user_mode_loop kernel/entry/common.c:111 [inline] > exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] > __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] > syscall_exit_to_user_mode+0x59/0x130 kernel/entry/common.c:218 > do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > read to 0xffff8881223aa3e8 of 8 bytes by task 50 on cpu 1: > __flush_work+0x42a/0x570 kernel/workqueue.c:4188 > flush_work kernel/workqueue.c:4229 [inline] > flush_delayed_work+0x66/0x70 kernel/workqueue.c:4251 > io_uring_try_cancel_requests+0x35b/0x370 io_uring/io_uring.c:3000 > io_ring_exit_work+0x148/0x500 io_uring/io_uring.c:2779 > process_one_work kernel/workqueue.c:3231 [inline] > process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312 > worker_thread+0x526/0x700 kernel/workqueue.c:3390 > kthread+0x1d1/0x210 kernel/kthread.c:389 > ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > value changed: 0x0000000000400000 -> 0xffff88810006c00d > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 UID: 0 PID: 50 Comm: kworker/u8:3 Not tainted 6.11.0-rc1-syzkaller-00334-ga5dbd76a8942 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 > Workqueue: iou_exit io_ring_exit_work > ================================================================== This looks like workqueue, CC'ing maintainers. Unsure if this is benign or not. #syz set subsystems: kernel -- Jens Axboe
