syzbot


INFO: task hung in show_console_dev

Status: auto-obsoleted due to no activity on 2025/09/10 13:40
Subsystems: kernel
[Documentation on labels]
First crash: 232d, last: 232d

Sample crash report:
INFO: task syz.3.1878:12348 blocked for more than 147 seconds.
      Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1878      state:D stack:24408 pid:12348 tgid:12341 ppid:5817   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 ___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
 __down_common kernel/locking/semaphore.c:293 [inline]
 __down+0x20/0x30 kernel/locking/semaphore.c:303
 down+0x74/0xa0 kernel/locking/semaphore.c:100
 console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
 show_console_dev+0xc1/0x600 fs/proc/consoles.c:43
 seq_read_iter+0x506/0x12c0 fs/seq_file.c:230
 proc_reg_read_iter+0x220/0x310 fs/proc/inode.c:299
 copy_splice_read+0x615/0xba0 fs/splice.c:363
 do_splice_read fs/splice.c:979 [inline]
 do_splice_read+0x285/0x370 fs/splice.c:953
 splice_direct_to_actor+0x2a1/0xa30 fs/splice.c:1083
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0x174/0x240 fs/splice.c:1227
 do_sendfile+0xb06/0xe50 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd598d8e929
RSP: 002b:00007fd599b34038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007fd598fb6080 RCX: 00007fd598d8e929
RDX: 0000000000000000 RSI: 000000000000000a RDI: 0000000000000009
RBP: 00007fd598e10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000020000023896 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fd598fb6080 R15: 00007ffd035ed8d8
 </TASK>
INFO: task syz.0.1877:12351 blocked for more than 147 seconds.
      Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1877      state:D stack:28888 pid:12351 tgid:12343 ppid:5820   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5396 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6785
 __schedule_loop kernel/sched/core.c:6863 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6878
 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
 ___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
 __down_common kernel/locking/semaphore.c:293 [inline]
 __down+0x20/0x30 kernel/locking/semaphore.c:303
 down+0x74/0xa0 kernel/locking/semaphore.c:100
 console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
 vcs_open+0x64/0xc0 drivers/tty/vt/vc_screen.c:763
 chrdev_open+0x231/0x6a0 fs/char_dev.c:414
 do_dentry_open+0x741/0x1c10 fs/open.c:964
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1de4/0x2cb0 fs/namei.c:4046
 do_filp_open+0x20b/0x470 fs/namei.c:4073
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
 do_sys_open fs/open.c:1452 [inline]
 __do_sys_openat fs/open.c:1468 [inline]
 __se_sys_openat fs/open.c:1463 [inline]
 __x64_sys_openat+0x174/0x210 fs/open.c:1463
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3dd818d290
RSP: 002b:00007f3dd8f24b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000102 RCX: 00007f3dd818d290
RDX: 0000000000000102 RSI: 00007f3dd8f24c10 RDI: 00000000ffffff9c
RBP: 00007f3dd8f24c10 R08: 0000000000000000 R09: 0023617363762f76
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 0000000000000000 R14: 00007f3dd83b6160 R15: 00007fff5cd353e8
 </TASK>

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/u8:0/12:
4 locks held by kworker/u8:1/13:
1 lock held by khungtaskd/31:
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8e5c4840 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:2/36:
4 locks held by kworker/u8:3/53:
1 lock held by kswapd0/86:
4 locks held by kworker/u8:5/1103:
4 locks held by kworker/u8:6/1148:
4 locks held by kworker/u8:7/1169:
2 locks held by kworker/R-bat_e/3399:
4 locks held by kworker/u8:8/3472:
9 locks held by kworker/u8:9/3549:
1 lock held by klogd/5180:
3 locks held by udevd/5191:
1 lock held by dhcpcd/5485:
2 locks held by dhcpcd/5486:
2 locks held by crond/5560:
2 locks held by getty/5584:
 #0: ffff8880370020a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by kworker/0:7/5950:
3 locks held by kworker/u8:10/6674:
4 locks held by kworker/u8:11/6931:
 #0: ffff88802875f948 ((wq_completion)wg-kex-wg2#7){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9001b50fd10 ((work_completion)(&peer->transmit_handshake_work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff888028239308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0xec/0x650 drivers/net/wireguard/noise.c:529
 #3: ffff8880291c8d20 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_create_initiation+0x100/0x650 drivers/net/wireguard/noise.c:530
1 lock held by syz.4.667/8514:
4 locks held by kworker/0:8/8684:
 #0: ffff8880595cf948 ((wq_completion)wg-kex-wg2#8){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
 #1: ffffc9000ba67d10 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((__typeof__(*((worker))) *)(( unsigned long)((worker))))); (typeof((__typeof__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
 #2: ffff888028239308 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x1c2/0x880 drivers/net/wireguard/noise.c:598
 #3: ffff8880291c8d20 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_initiation+0x5ac/0x880 drivers/net/wireguard/noise.c:632
3 locks held by kworker/0:9/8685:
2 locks held by kworker/1:13/8691:
5 locks held by kworker/1:14/8692:
3 locks held by kworker/1:15/8693:
6 locks held by syz.1.1861/12292:
2 locks held by syz.2.1879/12345:
2 locks held by syz.3.1878/12348:
 #0: ffff8880326bfc30 (&p->lock){+.+.}-{4:4}, at: seq_read_iter+0xe1/0x12c0 fs/seq_file.c:182
 #1: ffffffff8e5b2748 (console_mutex){+.+.}-{4:4}, at: c_start+0x17/0x100 fs/proc/consoles.c:82
1 lock held by syz-executor/12362:

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
 watchdog+0xf70/0x12c0 kernel/hung_task.c:470
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 3549 Comm: kworker/u8:9 Not tainted 6.16.0-rc1-syzkaller-00010-g2c4a1f3fe03e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: wg-kex-wg0 wg_packet_handshake_send_worker
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:146 [inline]
RIP: 0010:lock_acquire kernel/locking/lockdep.c:5872 [inline]
RIP: 0010:lock_acquire+0x14f/0x350 kernel/locking/lockdep.c:5828
Code: 00 00 85 d2 0f 85 8c 00 00 00 9c 8f 04 24 fa 48 c7 c7 33 af f0 8d e8 40 56 e7 09 45 89 e0 89 e9 44 89 ea 65 ff 05 b9 82 34 12 <48> 81 24 24 00 02 00 00 44 89 f6 48 89 df 6a 00 6a 00 6a 00 ff b4
RSP: 0018:ffffc900000067d0 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffffffff8e5c4840 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8df0af33 RDI: ffffffff8c1570a0
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000122b6 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124754000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd29db3dff8 CR3: 0000000077a9f000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 00000000000f010e DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:841 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x2d1/0x4d0 mm/slub.c:4745
 __skb_ext_put+0x102/0x2c0 net/core/skbuff.c:7157
 __skb_ext_del+0xf3/0x340 net/core/skbuff.c:7124
 skb_ext_del include/linux/skbuff.h:4892 [inline]
 nf_bridge_info_free net/bridge/br_netfilter_hooks.c:156 [inline]
 br_nf_dev_queue_xmit+0x7b7/0x2cb0 net/bridge/br_netfilter_hooks.c:922
 NF_HOOK include/linux/netfilter.h:317 [inline]
 NF_HOOK include/linux/netfilter.h:311 [inline]
 br_nf_post_routing+0x8e7/0x1190 net/bridge/br_netfilter_hooks.c:969
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623
 nf_hook+0x45e/0x780 include/linux/netfilter.h:272
 NF_HOOK include/linux/netfilter.h:315 [inline]
 br_forward_finish+0xcd/0x130 net/bridge/br_forward.c:66
 br_nf_hook_thresh+0x304/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_forward_finish+0x66a/0xba0 net/bridge/br_netfilter_hooks.c:665
 NF_HOOK include/linux/netfilter.h:317 [inline]
 NF_HOOK include/linux/netfilter.h:311 [inline]
 br_nf_forward_ip.part.0+0x609/0x810 net/bridge/br_netfilter_hooks.c:719
 br_nf_forward_ip net/bridge/br_netfilter_hooks.c:679 [inline]
 br_nf_forward+0xf0f/0x1be0 net/bridge/br_netfilter_hooks.c:776
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623
 nf_hook+0x45e/0x780 include/linux/netfilter.h:272
 NF_HOOK include/linux/netfilter.h:315 [inline]
 __br_forward+0x1be/0x5b0 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0xf1/0x180 net/bridge/br_forward.c:190
 br_flood+0x17c/0x650 net/bridge/br_forward.c:237
 br_handle_frame_finish+0xf2d/0x1ca0 net/bridge/br_input.c:221
 br_nf_hook_thresh+0x304/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0xad8/0x14b0 net/bridge/br_input.c:434
 __netif_receive_skb_core.constprop.0+0xa23/0x4a00 net/core/dev.c:5863
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5975
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6090
 process_backlog+0x442/0x15e0 net/core/dev.c:6442
 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:7414
 napi_poll net/core/dev.c:7478 [inline]
 net_rx_action+0xa9f/0xfe0 net/core/dev.c:7605
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 do_softirq kernel/softirq.c:480 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:467
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:407
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 fpregs_unlock arch/x86/include/asm/fpu/api.h:77 [inline]
 kernel_fpu_end+0x5e/0x70 arch/x86/kernel/fpu/core.c:476
 blake2s_compress+0x7f/0xe0 arch/x86/lib/crypto/blake2s-glue.c:46
 blake2s_final+0xc9/0x150 lib/crypto/blake2s.c:54
 hmac.constprop.0+0x252/0x420 drivers/net/wireguard/noise.c:325
 kdf.constprop.0+0x14b/0x280 drivers/net/wireguard/noise.c:367
 mix_precomputed_dh drivers/net/wireguard/noise.c:426 [inline]
 wg_noise_handshake_create_initiation+0x3b0/0x650 drivers/net/wireguard/noise.c:560
 wg_packet_send_handshake_initiation+0x19a/0x360 drivers/net/wireguard/send.c:34
 wg_packet_handshake_send_worker+0x1c/0x30 drivers/net/wireguard/send.c:51
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/12 13:37 upstream 2c4a1f3fe03e 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: task hung in show_console_dev
* Struck through repros no longer work on HEAD.