INFO: task syz.0.4214:20900 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.0.4214 state:D stack:0 pid:20900 tgid:20900 ppid:19421 task_flags:0x400040 flags:0x00000005 Call trace: [<81b6b994>] (__schedule) from [<81b6ce2c>] (__schedule_loop kernel/sched/core.c:7311 [inline]) [<81b6b994>] (__schedule) from [<81b6ce2c>] (schedule+0x2c/0xec kernel/sched/core.c:7326) r10:874e5e80 r9:84873d40 r8:86480800 r7:858f7758 r6:dfa71ea0 r5:dfa71e30 r4:84873d40 [<81b6ce00>] (schedule) from [<807a4f0c>] (request_wait_answer fs/fuse/dev.c:743 [inline]) [<81b6ce00>] (schedule) from [<807a4f0c>] (__fuse_request_send fs/fuse/dev.c:757 [inline]) [<81b6ce00>] (schedule) from [<807a4f0c>] (fuse_chan_send+0x390/0x47c fs/fuse/dev.c:833) r5:dfa71e30 r4:858f7700 [<807a4b7c>] (fuse_chan_send) from [<807b7394>] (__fuse_simple_request+0x5c/0x68 fs/fuse/req.c:69) r8:878cec80 r7:86c0ad40 r6:8675c700 r5:86a73900 r4:dfa71ea0 [<807b7338>] (__fuse_simple_request) from [<807acbc4>] (fuse_simple_request fs/fuse/fuse_i.h:1012 [inline]) [<807b7338>] (__fuse_simple_request) from [<807acbc4>] (fuse_flush+0x178/0x1b4 fs/fuse/file.c:504) r5:85539440 r4:874e5e80 [<807aca4c>] (fuse_flush) from [<8059aefc>] (filp_flush+0x38/0x88 fs/open.c:1520) r8:8675c740 r7:8653aa80 r6:0000001e r5:8675c700 r4:874e5e80 [<8059aec4>] (filp_flush) from [<8059af60>] (filp_close+0x14/0x28 fs/open.c:1533) r7:8653aa80 r6:0000001e r5:874e5e80 r4:8675c700 [<8059af4c>] (filp_close) from [<805ced88>] (__range_close fs/file.c:793 [inline]) [<8059af4c>] (filp_close) from [<805ced88>] (__do_sys_close_range fs/file.c:854 [inline]) [<8059af4c>] (filp_close) from [<805ced88>] (sys_close_range+0x18c/0x224 fs/file.c:818) r5:00000006 r4:8675c700 [<805cebfc>] (sys_close_range) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67) Exception stack(0xdfa71fa8 to 0xdfa71ff0) 1fa0: 00000000 00000000 00000003 0000001e 00000000 7ecbd920 1fc0: 00000000 00000000 00000000 000001b4 001d9546 ffffffff 00000000 003562e4 1fe0: 7ecbd848 7ecbd838 00028610 001309d0 r10:000001b4 r9:84873d40 r8:8020029c r7:000001b4 r6:00000000 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: [<80201998>] (dump_backtrace) from [<80201a8c>] (show_stack+0x18/0x1c arch/arm/kernel/traps.c:257) r7:60000093 r6:60000093 r5:82335878 r4:00000000 [<80201a74>] (show_stack) from [<8021ec68>] (__dump_stack lib/dump_stack.c:94 [inline]) [<80201a74>] (show_stack) from [<8021ec68>] (dump_stack_lvl+0x5c/0x70 lib/dump_stack.c:120) [<8021ec0c>] (dump_stack_lvl) from [<8021ec94>] (dump_stack+0x18/0x1c lib/dump_stack.c:129) r7:00000000 r6:00000013 r5:00000000 r4:00000001 [<8021ec7c>] (dump_stack) from [<81b54ffc>] (nmi_cpu_backtrace+0x150/0x170 lib/nmi_backtrace.c:122) [<81b54eac>] (nmi_cpu_backtrace) from [<81b55150>] (nmi_trigger_cpumask_backtrace+0x134/0x208 lib/nmi_backtrace.c:65) r7:82a0b150 r6:83320c40 r5:82a1c7b8 r4:ffffffff [<81b5501c>] (nmi_trigger_cpumask_backtrace) from [<802300d4>] (arch_trigger_cpumask_backtrace+0x18/0x1c arch/arm/kernel/smp.c:851) r9:82a0b2f0 r8:00000001 r7:82a1ce80 r6:82ccbe2c r5:00007f1b r4:00000048 [<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b5cc8c>] (trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]) [<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b5cc8c>] (__sys_info lib/sys_info.c:157 [inline]) [<802300bc>] (arch_trigger_cpumask_backtrace) from [<81b5cc8c>] (sys_info+0x68/0xa8 lib/sys_info.c:165) [<81b5cc24>] (sys_info) from [<80390a58>] (check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]) [<81b5cc24>] (sys_info) from [<80390a58>] (watchdog+0x3a0/0x848 kernel/hung_task.c:561) r5:00007f1b r4:0000000a [<803906b8>] (watchdog) from [<802827ac>] (kthread+0x11c/0x154 kernel/kthread.c:436) r10:00000000 r9:df819e60 r8:831d5600 r7:00000000 r6:803906b8 r5:83320c40 r4:833dd080 [<80282690>] (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 r5:80282690 r4:833dd080 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 3100 Comm: sshd-session Tainted: G L syzkaller #0 PREEMPT Tainted: [L]=SOFTLOCKUP Hardware name: ARM-Versatile Express PC is at __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] PC is at _raw_spin_unlock_irqrestore+0x28/0x54 kernel/locking/spinlock.c:198 LR is at __mod_timer+0x140/0x408 kernel/time/timer.c:1139 pc : [<81b762f4>] lr : [<80330288>] psr: 20030013 sp : df805b10 ip : df805b20 fp : df805b1c r10: ffffffff r9 : 82a03d80 r8 : 00033305 r7 : 00000000 r6 : ddddafc0 r5 : ddddafc0 r4 : 85bc4150 r3 : 00004c8e r2 : 00000006 r1 : 40030013 r0 : ddddafc0 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none Control: 30c5387d Table: 85d50b80 DAC: 00000000 Call trace: frame pointer underflow [<81b762cc>] (_raw_spin_unlock_irqrestore) from [<80330288>] (__mod_timer+0x140/0x408 kernel/time/timer.c:1139) [<80330148>] (__mod_timer) from [<8033057c>] (mod_timer+0x14/0x18 kernel/time/timer.c:1195) r10:85bc3e00 r9:0000022e r8:03e7b6d0 r7:84858000 r6:82e394c0 r5:00000004 r4:85bc3e00 [<80330568>] (mod_timer) from [<8162f8f4>] (sk_reset_timer+0x20/0x70 net/core/sock.c:3724) [<8162f8d4>] (sk_reset_timer) from [<818605cc>] (tcp_send_delayed_ack+0xb4/0x114 net/ipv4/tcp_output.c:4462) r5:00000004 r4:85bc3e00 [<81860518>] (tcp_send_delayed_ack) from [<81849dcc>] (__tcp_ack_snd_check+0x1f0/0x21c net/ipv4/tcp_input.c:6149) r7:84858000 r6:82e394c0 r5:00000001 r4:85bc3e00 [<81849bdc>] (__tcp_ack_snd_check) from [<818548ac>] (tcp_ack_snd_check net/ipv4/tcp_input.c:6198 [inline]) [<81849bdc>] (__tcp_ack_snd_check) from [<818548ac>] (tcp_ack_snd_check net/ipv4/tcp_input.c:6192 [inline]) [<81849bdc>] (__tcp_ack_snd_check) from [<818548ac>] (tcp_rcv_established+0x46c/0xc98 net/ipv4/tcp_input.c:6692) r6:878e00e0 r5:84dfab40 r4:85bc3e00 [<81854440>] (tcp_rcv_established) from [<81867550>] (tcp_v4_do_rcv+0x1c8/0x3c4 net/ipv4/tcp_ipv4.c:1854) r10:85bc3e00 r9:00000001 r8:82e394c0 r7:00000020 r6:86771a80 r5:85bc3e00 r4:84dfab40 [<81867388>] (tcp_v4_do_rcv) from [<8186935c>] (tcp_v4_rcv+0xb90/0x1314 net/ipv4/tcp_ipv4.c:2248) r7:00000020 r6:85bc3ef4 r5:00000001 r4:84dfab40 [<818687cc>] (tcp_v4_rcv) from [<8182bd08>] (ip_protocol_deliver_rcu+0x38/0x268 net/ipv4/ip_input.c:207) r10:ddde66a0 r9:00000000 r8:00000000 r7:82e394c0 r6:82a19104 r5:84dfab40 r4:82a04f6c [<8182bcd0>] (ip_protocol_deliver_rcu) from [<8182bfd8>] (ip_local_deliver_finish+0xa0/0x204 net/ipv4/ip_input.c:241) r9:ddde6588 r8:00000040 r7:00000000 r6:00000014 r5:82e394c0 r4:84dfab40 [<8182bf38>] (ip_local_deliver_finish) from [<8182c1b8>] (NF_HOOK include/linux/netfilter.h:318 [inline]) [<8182bf38>] (ip_local_deliver_finish) from [<8182c1b8>] (NF_HOOK include/linux/netfilter.h:312 [inline]) [<8182bf38>] (ip_local_deliver_finish) from [<8182c1b8>] (ip_local_deliver+0x7c/0x10c net/ipv4/ip_input.c:262) r7:00000000 r6:82e394c0 r5:83975000 r4:84dfab40 [<8182c13c>] (ip_local_deliver) from [<8182b968>] (dst_input include/net/dst.h:480 [inline]) [<8182c13c>] (ip_local_deliver) from [<8182b968>] (ip_rcv_finish+0x98/0xb0 net/ipv4/ip_input.c:492) r6:83975000 r5:82e394c0 r4:84dfab40 [<8182b8d0>] (ip_rcv_finish) from [<8182c32c>] (NF_HOOK include/linux/netfilter.h:318 [inline]) [<8182b8d0>] (ip_rcv_finish) from [<8182c32c>] (NF_HOOK include/linux/netfilter.h:312 [inline]) [<8182b8d0>] (ip_rcv_finish) from [<8182c32c>] (ip_rcv+0xe4/0xec net/ipv4/ip_input.c:612) r7:00000000 r6:82e394c0 r5:83975000 r4:84dfab40 [<8182c248>] (ip_rcv) from [<81665048>] (__netif_receive_skb_one_core+0x60/0x84 net/core/dev.c:6216) r6:00000000 r5:8182c248 r4:83975000 [<81664fe8>] (__netif_receive_skb_one_core) from [<816650b4>] (__netif_receive_skb+0x18/0x5c net/core/dev.c:6329) r5:00000001 r4:84dfab40 [<8166509c>] (__netif_receive_skb) from [<81665400>] (process_backlog+0xa0/0x17c net/core/dev.c:6680) r5:00000001 r4:84dfab40 [<81665360>] (process_backlog) from [<81665be0>] (__napi_poll+0x34/0x268 net/core/dev.c:7739) r10:df805ec8 r9:00000000 r8:0000012c r7:00000040 r6:df805ec3 r5:ddde66a0 r4:00000001 [<81665bac>] (__napi_poll) from [<81666170>] (napi_poll net/core/dev.c:7802 [inline]) [<81665bac>] (__napi_poll) from [<81666170>] (net_rx_action+0x35c/0x3e8 net/core/dev.c:7959) r9:00000000 r8:0000012c r7:ddde66a0 r6:ddde66a4 r5:ddde6580 r4:ffffffff [<81665e14>] (net_rx_action) from [<8025b1a4>] (handle_softirqs+0x160/0x4e4 kernel/softirq.c:622) r10:84858000 r9:00000008 r8:00000101 r7:0000000c r6:00000004 r5:00000003 r4:82a0308c [<8025b044>] (handle_softirqs) from [<802012f0>] (__do_softirq+0x14/0x18 kernel/softirq.c:656) r10:00000000 r9:828d55cc r8:00000000 r7:83975000 r6:00000000 r5:00000001 r4:60030013 [<802012dc>] (__do_softirq) from [<8022829c>] (____do_softirq+0x10/0x14 arch/arm/kernel/irq.c:77) [<8022828c>] (____do_softirq) from [<81b34cc8>] (call_with_stack+0x1c/0x20 arch/arm/lib/call_with_stack.S:40) [<81b34cac>] (call_with_stack) from [<802282d8>] (do_softirq_own_stack+0x38/0x3c arch/arm/kernel/irq.c:82) [<802282a0>] (do_softirq_own_stack) from [<8025b818>] (do_softirq kernel/softirq.c:523 [inline]) [<802282a0>] (do_softirq_own_stack) from [<8025b818>] (do_softirq+0x5c/0x64 kernel/softirq.c:510) [<8025b7bc>] (do_softirq) from [<8025b8ec>] (__local_bh_enable_ip+0xcc/0xd0 kernel/softirq.c:450) r5:00000001 r4:84858000 [<8025b820>] (__local_bh_enable_ip) from [<81662448>] (local_bh_enable include/linux/bottom_half.h:33 [inline]) [<8025b820>] (__local_bh_enable_ip) from [<81662448>] (rcu_read_unlock_bh include/linux/rcupdate.h:914 [inline]) [<8025b820>] (__local_bh_enable_ip) from [<81662448>] (__dev_queue_xmit+0x77c/0x126c net/core/dev.c:4913) r5:8335ca00 r4:00000000 [<81661ccc>] (__dev_queue_xmit) from [<8182fe1c>] (dev_queue_xmit include/linux/netdevice.h:3448 [inline]) [<81661ccc>] (__dev_queue_xmit) from [<8182fe1c>] (neigh_hh_output include/net/neighbour.h:544 [inline]) [<81661ccc>] (__dev_queue_xmit) from [<8182fe1c>] (neigh_output include/net/neighbour.h:558 [inline]) [<81661ccc>] (__dev_queue_xmit) from [<8182fe1c>] (ip_finish_output2+0x36c/0x790 net/ipv4/ip_output.c:236) r10:82e394c0 r9:00000000 r8:00000010 r7:00000000 r6:0000000e r5:84dfab40 r4:85960600 [<8182fab0>] (ip_finish_output2) from [<81831148>] (__ip_finish_output.part.0+0x9c/0x150 net/ipv4/ip_output.c:314) r8:83975000 r7:82e394c0 r6:0000ffff r5:85bc3640 r4:84dfab40 [<818310ac>] (__ip_finish_output.part.0) from [<81831238>] (__ip_finish_output+0x3c/0x40 net/ipv4/ip_output.c:304) r9:00000000 r8:83975000 r7:00000001 r6:85bc3640 r5:82e394c0 r4:84dfab40 [<818311fc>] (__ip_finish_output) from [<818312a4>] (ip_finish_output net/ipv4/ip_output.c:324 [inline]) [<818311fc>] (__ip_finish_output) from [<818312a4>] (NF_HOOK_COND include/linux/netfilter.h:307 [inline]) [<818311fc>] (__ip_finish_output) from [<818312a4>] (ip_output+0x68/0x104 net/ipv4/ip_output.c:437) [<8183123c>] (ip_output) from [<81832a98>] (dst_output include/net/dst.h:470 [inline]) [<8183123c>] (ip_output) from [<81832a98>] (ip_local_out net/ipv4/ip_output.c:131 [inline]) [<8183123c>] (ip_output) from [<81832a98>] (__ip_queue_xmit+0x190/0x528 net/ipv4/ip_output.c:533) r8:85bc38f8 r7:86771a80 r6:00000001 r5:85bc3640 r4:84dfab40 [<81832908>] (__ip_queue_xmit) from [<81832e44>] (ip_queue_xmit+0x14/0x18 net/ipv4/ip_output.c:547) r10:0100007f r9:fd7bfdcf r8:0000022d r7:00000020 r6:0100007f r5:85bc3640 r4:84dfab40 [<81832e30>] (ip_queue_xmit) from [<8185aa4c>] (__tcp_transmit_skb+0x658/0x10a4 net/ipv4/tcp_output.c:1716) [<8185a3f4>] (__tcp_transmit_skb) from [<8185c9f4>] (tcp_transmit_skb net/ipv4/tcp_output.c:1734 [inline]) [<8185a3f4>] (__tcp_transmit_skb) from [<8185c9f4>] (tcp_write_xmit+0x4dc/0x19e4 net/ipv4/tcp_output.c:3062) r10:19f944aa r9:85bc376c r8:00000000 r7:0000ffcb r6:0000ffcb r5:85bc3640 r4:84dfaa80 [<8185c518>] (tcp_write_xmit) from [<8185df34>] (__tcp_push_pending_frames+0x38/0x11c net/ipv4/tcp_output.c:3245) r10:00000125 r9:84858000 r8:838b9f00 r7:00000000 r6:85bc376c r5:84dfaa80 r4:85bc3640 [<8185defc>] (__tcp_push_pending_frames) from [<8185f414>] (tcp_send_fin+0x60/0x2c8 net/ipv4/tcp_output.c:3844) r7:00000000 r6:85bc376c r5:84dfaa80 r4:85bc3640 [<8185f3b4>] (tcp_send_fin) from [<8184541c>] (tcp_shutdown+0x58/0x5c net/ipv4/tcp.c:3084) r7:00000000 r6:00000002 r5:00000084 r4:85bc3640 [<818453c4>] (tcp_shutdown) from [<81889f18>] (inet_shutdown+0xf4/0x100 net/ipv4/af_inet.c:931) r5:835731c0 r4:85bc3640 [<81889e24>] (inet_shutdown) from [<8162cd40>] (__sys_shutdown_sock net/socket.c:2550 [inline]) [<81889e24>] (inet_shutdown) from [<8162cd40>] (__sys_shutdown_sock net/socket.c:2544 [inline]) [<81889e24>] (inet_shutdown) from [<8162cd40>] (__sys_shutdown+0x78/0xa8 net/socket.c:2566) r7:00000001 r6:838b9f00 r5:835731c0 r4:00000000 [<8162ccc8>] (__sys_shutdown) from [<8162cd80>] (__do_sys_shutdown net/socket.c:2571 [inline]) [<8162ccc8>] (__sys_shutdown) from [<8162cd80>] (sys_shutdown+0x10/0x14 net/socket.c:2569) r9:84858000 r8:8020029c r7:00000125 r6:011631d8 r5:0055813c r4:0116e578 [<8162cd70>] (sys_shutdown) from [<80200060>] (ret_fast_syscall+0x0/0x1c arch/arm/mm/proc-v7.S:67) Exception stack(0xdf981fa8 to 0xdf981ff0) 1fa0: 0116e578 0055813c 00000009 00000001 00000000 00000000 1fc0: 0116e578 0055813c 011631d8 00000125 00000006 005500a8 00000000 00000003 1fe0: 00576ccc 7e8650dc 004f5820 769fb12c