On 8/23/21 12:36 PM, Pavel Begunkov wrote: > On 8/23/21 10:17 AM, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 86ed57fd8c93 Add linux-next specific files for 20210820 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=1565bd55300000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=f64eccb415bd479d >> dashboard link: https://syzkaller.appspot.com/bug?extid=b0c9d1588ae92866515f >> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 >> >> Unfortunately, I don't have any reproducer for this issue yet. >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+b0c9d1588ae92866515f@xxxxxxxxxxxxxxxxxxxxxxxxx > > false positive, will delete the warning with explanation There is a legit race though, a fix is sent. > > p.s. easily reproducible, we'll add a test covering cancel from io-wq > >> >> WARNING: CPU: 1 PID: 5870 at fs/io_uring.c:5975 io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975 >> Modules linked in: >> CPU: 0 PID: 5870 Comm: iou-wrk-5860 Not tainted 5.14.0-rc6-next-20210820-syzkaller #0 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 >> RIP: 0010:io_try_cancel_userdata+0x30f/0x540 fs/io_uring.c:5975 >> Code: 07 e8 e5 9d 95 ff 48 8b 7c 24 08 e8 ab 02 58 07 e9 6f fe ff ff e8 d1 9d 95 ff 41 bf 8e ff ff ff e9 5f fe ff ff e8 c1 9d 95 ff <0f> 0b 48 b8 00 00 00 00 00 fc ff df 4c 89 fa 48 c1 ea 03 80 3c 02 >> RSP: 0018:ffffc900055f7a88 EFLAGS: 00010293 >> RAX: 0000000000000000 RBX: ffff888181aa83c0 RCX: 0000000000000000 >> RDX: ffff88803fb88000 RSI: ffffffff81e0dacf RDI: ffff888181aa8410 >> RBP: ffff88803fb88000 R08: ffffffff899ad660 R09: ffffffff81e23c44 >> R10: 0000000000000027 R11: 000000000000000e R12: 1ffff92000abef53 >> R13: 0000000000000000 R14: ffff8880b34d0000 R15: ffff888181aa8420 >> FS: 00007f7a08d50700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 0000001b2c72e000 CR3: 0000000168b9b000 CR4: 00000000001506e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 >> Call Trace: >> io_async_cancel fs/io_uring.c:6014 [inline] >> io_issue_sqe+0x22d5/0x65a0 fs/io_uring.c:6407 >> io_wq_submit_work+0x1dc/0x300 fs/io_uring.c:6511 >> io_worker_handle_work+0xa45/0x1840 fs/io-wq.c:533 >> io_wqe_worker+0x2cc/0xbb0 fs/io-wq.c:582 >> ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 >> >> >> --- >> This report is generated by a bot. It may contain errors. >> See https://goo.gl/tpsmEJ for more information about syzbot. >> syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. >> >> syzbot will keep track of this issue. See: >> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. >> > -- Pavel Begunkov
