INFO: task syz-executor.4:19398 blocked for more than 144 seconds. Not tainted 5.14.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:25048 pid:19398 ppid: 7477 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:9609 [inline] io_uring_cancel_generic+0x5fe/0x740 fs/io_uring.c:9689 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: 0033:0x4665f9 RSP: 002b:00007fc7a2cf6188 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: 0000000000000304 RBX: 000000000056bf80 RCX: 00000000004665f9 RDX: 0000000000000000 RSI: 0000000000000304 RDI: 0000000000000006 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007fc7a2cf6300 R15: 0000000000022000 Showing all locks held in the system: 2 locks held by kworker/u4:1/10: 1 lock held by khungtaskd/27: #0: ffffffff8b97fda0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6446 1 lock held by in:imklog/6234: #0: ffff888078c759f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 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:106 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: 9380 Comm: kworker/0:5 Not tainted 5.14.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events nsim_dev_trap_report_work RIP: 0010:check_kcov_mode+0x2e/0x40 kernel/kcov.c:174 Code: eb 8b 7e 89 c2 81 e2 00 01 00 00 a9 00 01 ff 00 74 10 31 c0 85 d2 74 15 8b 96 3c 15 00 00 85 d2 74 0b 8b 86 18 15 00 00 39 f8 <0f> 94 c0 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 31 c0 65 8b RSP: 0018:ffffc90024247b10 EFLAGS: 00000093 RAX: 0000000000000000 RBX: 00000000000000ac RCX: ffff88823bdccf00 RDX: 0000000000000000 RSI: ffff88817d730000 RDI: 0000000000000003 RBP: ffff88823bdccf00 R08: ffff88823bdcc7af R09: 00000000ffffffac R10: ffffffff81bd7863 R11: 00000000000000ac R12: ffff88823bdcc7af R13: ffffffff902b1818 R14: ffff88823bdccf00 R15: 00000000ffffffac FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f271134d018 CR3: 000000000b68e000 CR4: 00000000001526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: write_comp_data kernel/kcov.c:218 [inline] __sanitizer_cov_trace_cmp8+0x1d/0x70 kernel/kcov.c:264 for_each_canary mm/kfence/core.c:248 [inline] kfence_guarded_free+0x183/0x940 mm/kfence/core.c:386 __kfence_free+0x70/0x150 mm/kfence/core.c:817 do_slab_free mm/slub.c:3471 [inline] slab_free mm/slub.c:3484 [inline] kmem_cache_free+0x594/0x5b0 mm/slub.c:3499 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:699 __kfree_skb net/core/skbuff.c:756 [inline] consume_skb net/core/skbuff.c:911 [inline] consume_skb+0xcf/0x160 net/core/skbuff.c:905 nsim_dev_trap_report drivers/net/netdevsim/dev.c:737 [inline] nsim_dev_trap_report_work+0x86f/0xbd0 drivers/net/netdevsim/dev.c:762 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: eb 8b jmp 0xffffff8d 2: 7e 89 jle 0xffffff8d 4: c2 81 e2 retq $0xe281 7: 00 01 add %al,(%rcx) 9: 00 00 add %al,(%rax) b: a9 00 01 ff 00 test $0xff0100,%eax 10: 74 10 je 0x22 12: 31 c0 xor %eax,%eax 14: 85 d2 test %edx,%edx 16: 74 15 je 0x2d 18: 8b 96 3c 15 00 00 mov 0x153c(%rsi),%edx 1e: 85 d2 test %edx,%edx 20: 74 0b je 0x2d 22: 8b 86 18 15 00 00 mov 0x1518(%rsi),%eax 28: 39 f8 cmp %edi,%eax * 2a: 0f 94 c0 sete %al <-- trapping instruction 2d: c3 retq 2e: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 35: 00 00 00 00 39: 0f 1f 00 nopl (%rax) 3c: 31 c0 xor %eax,%eax 3e: 65 gs 3f: 8b .byte 0x8b