INFO: task syz-executor376:8310 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor376 D29984 8310 8112 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619 __mutex_lock_common kernel/locking/mutex.c:1016 [inline] __mutex_lock+0x5f0/0x1190 kernel/locking/mutex.c:1078 mutex_lock_double kernel/events/core.c:10470 [inline] __perf_event_ctx_lock_double kernel/events/core.c:10529 [inline] __do_sys_perf_event_open kernel/events/core.c:10784 [inline] __se_sys_perf_event_open+0x1863/0x2720 kernel/events/core.c:10549 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f725c923a99 Code: Bad RIP value. RSP: 002b:00007f725c8b4318 EFLAGS: 00000246 ORIG_RAX: 000000000000012a RAX: ffffffffffffffda RBX: 00007f725c9ab3f8 RCX: 00007f725c923a99 RDX: 0000000000000000 RSI: 00000000ffffffff RDI: 0000000020000000 RBP: 00007f725c9ab3f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 00007f725c9ab3fc R13: 00007fff59d0486f R14: 00007f725c8b4400 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1570: #0: 00000000a53a26b4 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by in:imklog/7821: #0: 00000000999b29e5 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 2 locks held by syz-executor376/8310: #0: 00000000186587b9 (&cpuctx_mutex){+.+.}, at: mutex_lock_double kernel/events/core.c:10469 [inline] #0: 00000000186587b9 (&cpuctx_mutex){+.+.}, at: __perf_event_ctx_lock_double kernel/events/core.c:10529 [inline] #0: 00000000186587b9 (&cpuctx_mutex){+.+.}, at: __do_sys_perf_event_open kernel/events/core.c:10784 [inline] #0: 00000000186587b9 (&cpuctx_mutex){+.+.}, at: __se_sys_perf_event_open+0x1856/0x2720 kernel/events/core.c:10549 #1: 00000000186587b9 (&cpuctx_mutex/1){+.+.}, at: mutex_lock_double kernel/events/core.c:10470 [inline] #1: 00000000186587b9 (&cpuctx_mutex/1){+.+.}, at: __perf_event_ctx_lock_double kernel/events/core.c:10529 [inline] #1: 00000000186587b9 (&cpuctx_mutex/1){+.+.}, at: __do_sys_perf_event_open kernel/events/core.c:10784 [inline] #1: 00000000186587b9 (&cpuctx_mutex/1){+.+.}, at: __se_sys_perf_event_open+0x1863/0x2720 kernel/events/core.c:10549 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4687 Comm: systemd-journal Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:97 Code: ff 48 89 df e8 11 dd 35 00 e9 ab fe ff ff 4c 89 ef e8 04 dd 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e 81 e2 RSP: 0018:ffff8880a122fa30 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8167ada7 RDX: 0000000000000000 RSI: ffff8880a1220440 RDI: 0000000000000005 RBP: ffff8880a13b1300 R08: ffff8880a13b2cf0 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000000 R12: ffff8880a122fba8 R13: 0000000000000000 R14: ffff8880a13b2d30 R15: ffffffff814d4fc0 FS: 00007f06022b58c0(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f05ff685000 CR3: 00000000a1295000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: trace_hardirqs_off+0x50/0x200 kernel/trace/trace_preemptirq.c:40 devkmsg_poll+0xce/0x210 kernel/printk/printk.c:952 vfs_poll include/linux/poll.h:90 [inline] ep_item_poll+0x14a/0x3e0 fs/eventpoll.c:890 ep_send_events_proc+0x1e1/0xb50 fs/eventpoll.c:1661 ep_scan_ready_list+0x285/0x9a0 fs/eventpoll.c:706 ep_send_events fs/eventpoll.c:1711 [inline] ep_poll+0x36f/0xcb0 fs/eventpoll.c:1838 do_epoll_wait+0x1aa/0x200 fs/eventpoll.c:2190 __do_sys_epoll_wait fs/eventpoll.c:2200 [inline] __se_sys_epoll_wait fs/eventpoll.c:2197 [inline] __x64_sys_epoll_wait+0x93/0xf0 fs/eventpoll.c:2197 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f060157e2e3 Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 29 54 2b 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 0b c2 00 00 48 89 04 24 RSP: 002b:00007ffe14e97578 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 0000561400e901e0 RCX: 00007f060157e2e3 RDX: 0000000000000013 RSI: 00007ffe14e97580 RDI: 0000000000000008 RBP: 00007ffe14e97770 R08: 00007ffe14f62000 R09: 000000b919d0e1c4 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe14e97580 R13: 0000000000000001 R14: 0000000000000000 R15: 0005e0496f9104e2 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 48 89 df mov %rbx,%rdi 3: e8 11 dd 35 00 callq 0x35dd19 8: e9 ab fe ff ff jmpq 0xfffffeb8 d: 4c 89 ef mov %r13,%rdi 10: e8 04 dd 35 00 callq 0x35dd19 15: e9 23 fe ff ff jmpq 0xfffffe3d 1a: 90 nop 1b: 90 nop 1c: 90 nop 1d: 90 nop 1e: 90 nop 1f: 90 nop 20: 90 nop 21: 90 nop 22: 90 nop 23: 90 nop 24: 90 nop 25: 90 nop 26: 90 nop 27: 90 nop 28: 90 nop * 29: 48 8b 34 24 mov (%rsp),%rsi <-- trapping instruction 2d: 65 48 8b 04 25 c0 df mov %gs:0x1dfc0,%rax 34: 01 00 36: 65 8b 15 cc 59 9f 7e mov %gs:0x7e9f59cc(%rip),%edx # 0x7e9f5a09 3d: 81 .byte 0x81 3e: e2 .byte 0xe2