INFO: task syz.9.5112:4824 blocked for more than 430 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.9.5112 state:D stack:0 pid:4824 tgid:4822 ppid:1498 task_flags:0x400040 flags:0x00000001 Call trace: [<81aeb20c>] (__schedule) from [<81aec620>] (__schedule_loop kernel/sched/core.c:6993 [inline]) [<81aeb20c>] (__schedule) from [<81aec620>] (schedule+0x2c/0x134 kernel/sched/core.c:7008) r10:8506e580 r9:8506e6b4 r8:00000001 r7:828044dc r6:8506e580 r5:00000000 r4:8790bd40 [<81aec5f4>] (schedule) from [<8034b2b0>] (futex_hash_allocate+0x3ec/0x4d4 kernel/futex/core.c:1829) r5:00000000 r4:87c00000 [<8034aec4>] (futex_hash_allocate) from [<8034c898>] (futex_hash_prctl+0x70/0x84 kernel/futex/core.c:1958) r10:00000000 r9:8790bd40 r8:00004000 r7:00000001 r6:00000000 r5:0000004e r4:ffffffda [<8034c828>] (futex_hash_prctl) from [<8026f950>] (__do_sys_prctl kernel/sys.c:2885 [inline]) [<8034c828>] (futex_hash_prctl) from [<8026f950>] (sys_prctl+0x474/0xb10 kernel/sys.c:2534) r5:0000004e r4:ffffffda [<8026f4dc>] (sys_prctl) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67) Exception stack(0xdfdc9fa8 to 0xdfdc9ff0) 9fa0: 00000000 00000000 0000004e 00000001 00004000 00000000 9fc0: 00000000 00000000 003463b0 000000ac 00346378 00000000 003d0f00 76ef60dc 9fe0: 76ef5e88 76ef5e78 00018bc4 00130300 r10:000000ac r9:8790bd40 r8:8020029c r7:000000ac r6:003463b0 r5:00000000 r4:00000000 NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 29 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: ARM-Versatile Express Call trace: [<80201a14>] (dump_backtrace) from [<80201b08>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:60000093 r6:60000093 r5:822a8a40 r4:00000000 [<80201af0>] (show_stack) from [<8021e410>] (__dump_stack lib/dump_stack.c:94 [inline]) [<80201af0>] (show_stack) from [<8021e410>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120) [<8021e3b4>] (dump_stack_lvl) from [<8021e43c>] (dump_stack+0x18/0x1c lib/dump_stack.c:129) r7:00000000 r6:00000013 r5:00000000 r4:00000001 [<8021e424>] (dump_stack) from [<81ad4c3c>] (nmi_cpu_backtrace+0x150/0x170 lib/nmi_backtrace.c:113) [<81ad4aec>] (nmi_cpu_backtrace) from [<81ad4d8c>] (nmi_trigger_cpumask_backtrace+0x130/0x1d8 lib/nmi_backtrace.c:62) r7:00000000 r6:8280c550 r5:8281af38 r4:ffffffff [<81ad4c5c>] (nmi_trigger_cpumask_backtrace) from [<8022f124>] (arch_trigger_cpumask_backtrace+0x18/0x1c arch/arm/kernel/smp.c:852) r9:82ac7834 r8:8280c6d8 r7:0006a540 r6:8790c528 r5:82804d80 r4:00000048 [<8022f10c>] (arch_trigger_cpumask_backtrace) from [<81adc87c>] (trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]) [<8022f10c>] (arch_trigger_cpumask_backtrace) from [<81adc87c>] (__sys_info lib/sys_info.c:157 [inline]) [<8022f10c>] (arch_trigger_cpumask_backtrace) from [<81adc87c>] (sys_info+0x68/0xa8 lib/sys_info.c:165) [<81adc814>] (sys_info) from [<80385260>] (check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]) [<81adc814>] (sys_info) from [<80385260>] (watchdog+0x59c/0x8d8 kernel/hung_task.c:515) r5:82804d80 r4:878c0b14 [<80384cc4>] (watchdog) from [<802814a0>] (kthread+0x11c/0x154 kernel/kthread.c:436) r10:00000000 r9:df819e60 r8:83385880 r7:00000000 r6:80384cc4 r5:833d0c40 r4:8332a640 [<80281384>] (kthread) from [<80200114>] (ret_from_fork+0x14/0x20 arch/arm/kernel/entry-common.S:137) Exception stack(0xdf8d5fb0 to 0xdf8d5ff8) 5fa0: 00000000 00000000 00000000 00000000 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000 r9:00000000 r8:00000000 r7:00000000 r6:00000000 r5:80281384 r4:8332a640 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 8385 Comm: syz.0.6051 Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: ARM-Versatile Express PC is at kmap_local_sched_in kernel/sched/core.c:5061 [inline] PC is at finish_task_switch+0x90/0x294 kernel/sched/core.c:5163 LR is at __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] LR is at _raw_spin_unlock+0x2c/0x50 kernel/locking/spinlock.c:186 pc : [<8028ebd0>] lr : [<81af5614>] psr: 200b0013 sp : ec665d18 ip : ec665d08 fp : ec665d5c r10: 00000001 r9 : 8794ee40 r8 : 00000000 r7 : 00000000 r6 : 81aeb6e8 r5 : ddde5400 r4 : 00000000 r3 : 8794ee40 r2 : 00000001 r1 : 822a8a40 r0 : 00000001 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 30c5387d Table: 86b55380 DAC: 00000000 Call trace: [<8028eb40>] (finish_task_switch) from [<81aeb6e8>] (context_switch kernel/sched/core.c:5301 [inline]) [<8028eb40>] (finish_task_switch) from [<81aeb6e8>] (__schedule+0x4dc/0x13e8 kernel/sched/core.c:6911) r10:00000001 r9:8506e1c0 r8:00000000 r7:00000000 r6:8794ee40 r5:ddde5400 r4:839e8c40 [<81aeb20c>] (__schedule) from [<81aec620>] (__schedule_loop kernel/sched/core.c:6993 [inline]) [<81aeb20c>] (__schedule) from [<81aec620>] (schedule+0x2c/0x134 kernel/sched/core.c:7008) r10:00000000 r9:00000000 r8:00000000 r7:00000002 r6:003462e0 r5:00000000 r4:8794ee40 [<81aec5f4>] (schedule) from [<80350a38>] (futex_do_wait+0x44/0x74 kernel/futex/waitwake.c:358) r5:00000000 r4:ec665e20 [<803509f4>] (futex_do_wait) from [<80351260>] (__futex_wait+0x98/0x104 kernel/futex/waitwake.c:687) r5:8794ee40 r4:00000000 [<803511c8>] (__futex_wait) from [<8035134c>] (futex_wait+0x80/0x10c kernel/futex/waitwake.c:715) r9:00000000 r8:0000c350 r7:003462e0 r6:00000000 r5:00000000 r4:00000002 [<803512cc>] (futex_wait) from [<8034ccdc>] (do_futex+0xb4/0x180 kernel/futex/syscalls.c:130) r10:000000f0 r9:00000000 r8:8794ee40 r7:00000000 r6:003462e0 r5:00000080 r4:00000000 [<8034cc28>] (do_futex) from [<8034d628>] (__do_sys_futex_time32 kernel/futex/syscalls.c:523 [inline]) [<8034cc28>] (do_futex) from [<8034d628>] (sys_futex_time32+0x11c/0x1bc kernel/futex/syscalls.c:506) r4:00000000 [<8034d50c>] (sys_futex_time32) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67) Exception stack(0xec665fa8 to 0xec665ff0) 5fa0: 00131688 ffffffff 003462e0 00000080 00000000 00000000 5fc0: 00131688 ffffffff 76fad7d4 000000f0 00330000 00000000 00000001 76fad0dc 5fe0: 76facf38 76facf28 00021520 00130300 r9:8794ee40 r8:8020029c r7:000000f0 r6:76fad7d4 r5:ffffffff r4:00131688