On Mon, 24 Apr 2023 at 09:19, syzbot <syzbot+cb265db2f3f3468ef436@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: 3a93e40326c8 Merge tag 'for-linus' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1280071ec80000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f7350c77b8056a38 > dashboard link: https://syzkaller.appspot.com/bug?extid=cb265db2f3f3468ef436 > compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/2122926bc9fe/disk-3a93e403.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/8392992358bc/vmlinux-3a93e403.xz > kernel image: https://storage.googleapis.com/syzbot-assets/6398a2d19a7e/bzImage-3a93e403.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+cb265db2f3f3468ef436@xxxxxxxxxxxxxxxxxxxxxxxxx I did not fully grasp what happens here, but it looks suspicious. The comment in io_timeout() says that it computes "events that need to occur for this timeout event to be satisfied". But if the range is racing, it marks a random set of events? > ================================================================== > BUG: KCSAN: data-race in __io_fill_cqe_req / io_timeout > > read-write to 0xffff888108bf8310 of 4 bytes by task 20447 on cpu 0: > io_get_cqe_overflow io_uring/io_uring.h:112 [inline] > io_get_cqe io_uring/io_uring.h:124 [inline] > __io_fill_cqe_req+0x6c/0x4d0 io_uring/io_uring.h:137 > io_fill_cqe_req io_uring/io_uring.h:165 [inline] > __io_req_complete_post+0x67/0x790 io_uring/io_uring.c:969 > io_req_complete_post io_uring/io_uring.c:1006 [inline] > io_req_task_complete+0xb9/0x110 io_uring/io_uring.c:1654 > handle_tw_list io_uring/io_uring.c:1184 [inline] > tctx_task_work+0x1fe/0x4d0 io_uring/io_uring.c:1246 > task_work_run+0x123/0x160 kernel/task_work.c:179 > get_signal+0xe5c/0xfe0 kernel/signal.c:2635 > arch_do_signal_or_restart+0x89/0x2b0 arch/x86/kernel/signal.c:306 > exit_to_user_mode_loop+0x6d/0xe0 kernel/entry/common.c:168 > exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:204 > __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] > syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297 > do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > read to 0xffff888108bf8310 of 4 bytes by task 20448 on cpu 1: > io_timeout+0x88/0x270 io_uring/timeout.c:546 > io_issue_sqe+0x147/0x660 io_uring/io_uring.c:1907 > io_queue_sqe io_uring/io_uring.c:2079 [inline] > io_submit_sqe io_uring/io_uring.c:2340 [inline] > io_submit_sqes+0x689/0xfe0 io_uring/io_uring.c:2450 > __do_sys_io_uring_enter io_uring/io_uring.c:3458 [inline] > __se_sys_io_uring_enter+0x1e5/0x1b70 io_uring/io_uring.c:3392 > __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3392 > 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: 0x00000c75 -> 0x00000c76 > > Reported by Kernel Concurrency Sanitizer on: > CPU: 1 PID: 20448 Comm: syz-executor.2 Not tainted 6.3.0-rc4-syzkaller-00025-g3a93e40326c8 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023 > ================================================================== > > > --- > 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. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/000000000000d7848305fa0fd413%40google.com.
