On 9/9/21 1:09 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 4b93c544e90e thunderbolt: test: split up test cases in tb_.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=111b2c2b300000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ac2f9cc43f6b17e4 > dashboard link: https://syzkaller.appspot.com/bug?extid=f62d3e0a4ea4f38f5326 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1152501b300000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16612dcd300000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+f62d3e0a4ea4f38f5326@xxxxxxxxxxxxxxxxxxxxxxxxx Let's check if it's related to recent changes for worker creation and signalling #syz test: https://github.com/isilence/linux.git syztest_iowq_workers > > INFO: task syz-executor687:8514 blocked for more than 143 seconds. > Not tainted 5.14.0-syzkaller #0 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:syz-executor687 state:D stack:27296 pid: 8514 ppid: 8479 flags:0x00024004 > Call Trace: > context_switch kernel/sched/core.c:4940 [inline] > __schedule+0x940/0x26f0 kernel/sched/core.c:6287 > schedule+0xd3/0x270 kernel/sched/core.c:6366 > schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1857 > do_wait_for_common kernel/sched/completion.c:85 [inline] > __wait_for_common kernel/sched/completion.c:106 [inline] > wait_for_common kernel/sched/completion.c:117 [inline] > wait_for_completion+0x176/0x280 kernel/sched/completion.c:138 > io_wq_exit_workers fs/io-wq.c:1162 [inline] > io_wq_put_and_exit+0x40c/0xc70 fs/io-wq.c:1197 > io_uring_clean_tctx fs/io_uring.c:9607 [inline] > io_uring_cancel_generic+0x5fe/0x740 fs/io_uring.c:9687 > io_uring_files_cancel include/linux/io_uring.h:16 [inline] > do_exit+0x265/0x2a30 kernel/exit.c:780 > do_group_exit+0x125/0x310 kernel/exit.c:922 > get_signal+0x47f/0x2160 kernel/signal.c:2868 > arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:865 > handle_signal_work kernel/entry/common.c:148 [inline] > exit_to_user_mode_loop kernel/entry/common.c:172 [inline] > exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:209 > __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] > syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302 > do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x445cd9 > RSP: 002b:00007fc657f4b308 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: 0000000000000001 RBX: 00000000004cb448 RCX: 0000000000445cd9 > RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00000000004cb44c > RBP: 00000000004cb440 R08: 000000000000000e R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000049b154 > R13: 0000000000000003 R14: 00007fc657f4b400 R15: 0000000000022000 > > Showing all locks held in the system: > 1 lock held by khungtaskd/1655: > #0: ffffffff8b97f960 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 > > ============================================= > > NMI backtrace for cpu 1 > CPU: 1 PID: 1655 Comm: khungtaskd Not tainted 5.14.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:88 [inline] > dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 > nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 > nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 > trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] > check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline] > watchdog+0xc1d/0xf50 kernel/hung_task.c:295 > kthread+0x3e5/0x4d0 kernel/kthread.c:319 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 > Sending NMI from CPU 1 to CPUs 0: > NMI backtrace for cpu 0 > CPU: 0 PID: 10 Comm: kworker/u4:1 Not tainted 5.14.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Workqueue: events_unbound toggle_allocation_gate > RIP: 0010:__text_poke+0x5f0/0x8c0 arch/x86/kernel/alternative.c:878 > Code: fb 48 8b 7c 24 60 e8 5f 67 0d 08 48 8b 4c 24 18 48 b8 00 00 00 00 00 fc ff df 48 c7 04 01 00 00 00 00 48 8b 84 24 98 00 00 00 <65> 48 2b 04 25 28 00 00 00 0f 85 2e 02 00 00 48 81 c4 a0 00 00 00 > RSP: 0018:ffffc90000cf7a00 EFLAGS: 00000286 > RAX: cfe52cf07638a100 RBX: 0000000000000007 RCX: 1ffff9200019ef48 > RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000001 > RBP: ffff888011eaa558 R08: 0000000000000000 R09: ffff888010db8123 > R10: ffffed10021b7024 R11: 000000000000003f R12: ffffffff81bcfd53 > R13: 0000000000000001 R14: 0000000000000d54 R15: ffffffff8baa9900 > FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007f442218f000 CR3: 000000000b68e000 CR4: 0000000000350ef0 > Call Trace: > text_poke_bp_batch+0x3d7/0x560 arch/x86/kernel/alternative.c:1178 > text_poke_flush arch/x86/kernel/alternative.c:1268 [inline] > text_poke_flush arch/x86/kernel/alternative.c:1265 [inline] > text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1275 > arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 > jump_label_update+0x1d5/0x430 kernel/jump_label.c:830 > static_key_enable_cpuslocked+0x1b1/0x260 kernel/jump_label.c:177 > static_key_enable+0x16/0x20 kernel/jump_label.c:190 > toggle_allocation_gate mm/kfence/core.c:623 [inline] > toggle_allocation_gate+0x100/0x390 mm/kfence/core.c:615 > process_one_work+0x9bf/0x16b0 kernel/workqueue.c:2297 > worker_thread+0x658/0x11f0 kernel/workqueue.c:2444 > kthread+0x3e5/0x4d0 kernel/kthread.c:319 > ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 > ---------------- > Code disassembly (best guess): > 0: fb sti > 1: 48 8b 7c 24 60 mov 0x60(%rsp),%rdi > 6: e8 5f 67 0d 08 callq 0x80d676a > b: 48 8b 4c 24 18 mov 0x18(%rsp),%rcx > 10: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax > 17: fc ff df > 1a: 48 c7 04 01 00 00 00 movq $0x0,(%rcx,%rax,1) > 21: 00 > 22: 48 8b 84 24 98 00 00 mov 0x98(%rsp),%rax > 29: 00 > * 2a: 65 48 2b 04 25 28 00 sub %gs:0x28,%rax <-- trapping instruction > 31: 00 00 > 33: 0f 85 2e 02 00 00 jne 0x267 > 39: 48 81 c4 a0 00 00 00 add $0xa0,%rsp > > > --- > 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. > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches > -- Pavel Begunkov
