INFO: task syz-executor122:26218 blocked for more than 140 seconds. Not tainted 4.14.284-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor122 D28912 26218 7982 0x00000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1e6/0x350 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:66 [inline] down_read+0x44/0x80 kernel/locking/rwsem.c:26 __do_page_fault+0x7b8/0xad0 arch/x86/mm/fault.c:1378 page_fault+0x45/0x50 arch/x86/entry/entry_64.S:1123 RIP: 79c2e4f0:0x7ffd79c2e510 RSP: 0064:0000000000000032 EFLAGS: 7f547e84a4bc INFO: task syz-executor122:26237 blocked for more than 140 seconds. Not tainted 4.14.284-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor122 D28976 26237 7982 0x80000004 Call Trace: context_switch kernel/sched/core.c:2811 [inline] __schedule+0x88b/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline] rwsem_down_read_failed+0x1e6/0x350 kernel/locking/rwsem-xadd.c:309 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94 __down_read arch/x86/include/asm/rwsem.h:66 [inline] down_read+0x44/0x80 kernel/locking/rwsem.c:26 exit_mm kernel/exit.c:511 [inline] do_exit+0x598/0x2850 kernel/exit.c:855 do_group_exit+0x100/0x2e0 kernel/exit.c:965 get_signal+0x38d/0x1ca0 kernel/signal.c:2412 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:792 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f547e7c76d9 RSP: 002b:00007f547df48218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f547e84a4b8 RCX: 00007f547e7c76d9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f547e84a4b8 RBP: 00007f547e84a4b0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f547e84a4bc R13: 00007ffd79c2e43f R14: 00007f547df48300 R15: 0000000000022000 Showing all locks held in the system: 1 lock held by khungtaskd/1533: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by syz-executor122/26218: #0: (&mm->mmap_sem){++++}, at: [] __do_page_fault+0x7b8/0xad0 arch/x86/mm/fault.c:1378 1 lock held by syz-executor122/26237: #0: (&mm->mmap_sem){++++}, at: [] exit_mm kernel/exit.c:511 [inline] #0: (&mm->mmap_sem){++++}, at: [] do_exit+0x598/0x2850 kernel/exit.c:855 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1533 Comm: khungtaskd Not tainted 4.14.284-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x281 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5b9/0xb40 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 23630 Comm: syz-executor122 Not tainted 4.14.284-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88809746c040 task.stack: ffff8880a32d0000 RIP: 0010:perf_log_itrace_start+0xa0/0x4a0 kernel/events/core.c:7450 RSP: 0018:ffff8880a32d7300 EFLAGS: 00000046 RAX: 1ffff11013705c8f RBX: 0000000000000000 RCX: ffffffff88fcd220 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88809b82e478 RBP: ffff8880a32d75a8 R08: 1ffffffff11993ac R09: ffff88823fff700f R10: ffff88823fff7017 R11: 000001702acbaaf0 R12: 1ffff1101465ae60 R13: ffff88809b82e1c0 R14: ffff88809b82e248 R15: 00000000000778e6 FS: 00007f547df69700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000100 CR3: 000000009c55f000 CR4: 00000000003406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: event_sched_in+0x447/0xdb0 kernel/events/core.c:2132 group_sched_in+0xfb/0x400 kernel/events/core.c:2174 ctx_flexible_sched_in kernel/events/core.c:3199 [inline] ctx_sched_in+0x1303/0x1860 kernel/events/core.c:3245 perf_event_sched_in+0x69/0xa0 kernel/events/core.c:2332 perf_event_context_sched_in kernel/events/core.c:3285 [inline] __perf_event_task_sched_in+0x5a3/0x8c0 kernel/events/core.c:3324 perf_event_task_sched_in include/linux/perf_event.h:1087 [inline] finish_task_switch+0x3c9/0x610 kernel/sched/core.c:2667 context_switch kernel/sched/core.c:2814 [inline] __schedule+0x893/0x1de0 kernel/sched/core.c:3387 schedule+0x8d/0x1b0 kernel/sched/core.c:3431 _synchronize_rcu_expedited+0x522/0x770 kernel/rcu/tree_exp.h:615 synchronize_rcu+0x98/0x130 kernel/rcu/tree_plugin.h:762 ring_buffer_attach+0x34a/0x5e0 kernel/events/core.c:5112 perf_mmap+0xd25/0x1390 kernel/events/core.c:5495 call_mmap include/linux/fs.h:1785 [inline] mmap_region+0xa1a/0x1220 mm/mmap.c:1717 do_mmap+0x5b3/0xcb0 mm/mmap.c:1495 do_mmap_pgoff include/linux/mm.h:2185 [inline] vm_mmap_pgoff+0x14e/0x1a0 mm/util.c:333 SYSC_mmap_pgoff mm/mmap.c:1545 [inline] SyS_mmap_pgoff+0x249/0x510 mm/mmap.c:1503 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x7f547e7c76d9 RSP: 002b:00007f547df691f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 000000000000001f RCX: 00007f547e7c76d9 RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffd000 RBP: 00007f547e84a4a0 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000011 R11: 0000000000000246 R12: 00007f547e84a4ac R13: 00007ffd79c2e43f R14: 00007f547df69300 R15: 0000000000022000 Code: c7 40 4c f3 f3 f3 f3 e8 7f d9 f0 ff 49 8d bd b8 02 00 00 48 89 f8 48 c1 e8 03 80 3c 18 00 0f 85 a1 03 00 00 49 8b 9d b8 02 00 00 <48> 85 db 49 0f 44 dd e8 54 d9 f0 ff 48 b8 00 00 00 00 00 fc ff ---------------- Code disassembly (best guess): 0: c7 40 4c f3 f3 f3 f3 movl $0xf3f3f3f3,0x4c(%rax) 7: e8 7f d9 f0 ff callq 0xfff0d98b c: 49 8d bd b8 02 00 00 lea 0x2b8(%r13),%rdi 13: 48 89 f8 mov %rdi,%rax 16: 48 c1 e8 03 shr $0x3,%rax 1a: 80 3c 18 00 cmpb $0x0,(%rax,%rbx,1) 1e: 0f 85 a1 03 00 00 jne 0x3c5 24: 49 8b 9d b8 02 00 00 mov 0x2b8(%r13),%rbx * 2b: 48 85 db test %rbx,%rbx <-- trapping instruction 2e: 49 0f 44 dd cmove %r13,%rbx 32: e8 54 d9 f0 ff callq 0xfff0d98b 37: 48 rex.W 38: b8 00 00 00 00 mov $0x0,%eax 3d: 00 fc add %bh,%ah 3f: ff .byte 0xff