syzbot

INFO: task udevd:4254 blocked for more than 143 seconds.
      Not tainted 5.15.179-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:udevd           state:D stack:25016 pid: 4254 ppid:  3546 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5029 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6375
 schedule+0x11b/0x1f0 kernel/sched/core.c:6458
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6517
 __mutex_lock_common+0xe34/0x25a0 kernel/locking/mutex.c:669
 __mutex_lock kernel/locking/mutex.c:729 [inline]
 mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
 device_lock include/linux/device.h:760 [inline]
 uevent_show+0x17e/0x340 drivers/base/core.c:2408
 dev_attr_show+0x50/0xb0 drivers/base/core.c:2110
 sysfs_kf_seq_show+0x313/0x4e0 fs/sysfs/file.c:61
 seq_read_iter+0x43a/0xd10 fs/seq_file.c:230
 call_read_iter include/linux/fs.h:2166 [inline]
 new_sync_read fs/read_write.c:404 [inline]
 vfs_read+0xa93/0xe10 fs/read_write.c:485
 ksys_read+0x1a2/0x2c0 fs/read_write.c:623
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f374a8bab6a
RSP: 002b:00007fffa59df4a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000563aaf303e70 RCX: 00007f374a8bab6a
RDX: 0000000000001000 RSI: 0000563aaf304050 RDI: 0000000000000008
RBP: 0000563aaf303e70 R08: 0000000000000008 R09: 0000000000000020
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000003fff R14: 00007fffa59df988 R15: 000000000000000a
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8cb1f4e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by kworker/u4:2/154:
 #0: ffff8880b8e3a318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
 #1: ffff88807e71e368 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xae/0x12c0 kernel/sched/core.c:4029
5 locks held by kworker/u4:3/866:
 #0: ffff8880175cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90003e1fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8dc37e10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x166/0xc90 net/core/net_namespace.c:572
 #3: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: ip_tunnel_delete_nets+0xca/0x360 net/ipv4/ip_tunnel.c:1146
 #4: ffffffff8cb23aa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #4: ffffffff8cb23aa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x280/0x740 kernel/rcu/tree_exp.h:845
3 locks held by kworker/u4:4/1236:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90005367d20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
6 locks held by kworker/1:3/2301:
 #0: ffff8881415a4538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc900068afd20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff8880242ec220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #2: ffff8880242ec220 (&dev->mutex){....}-{3:3}, at: hub_event+0x208/0x54c0 drivers/usb/core/hub.c:5781
 #3: ffff888079a9d220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #3: ffff888079a9d220 (&dev->mutex){....}-{3:3}, at: __device_attach+0x8a/0x570 drivers/base/dd.c:954
 #4: ffff8880257961a8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #4: ffff8880257961a8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x8a/0x570 drivers/base/dd.c:954
 #5: ffffffff8c9cf950 (umhelper_sem){++++}-{3:3}, at: usermodehelper_read_trylock+0x138/0x360 kernel/umh.c:217
2 locks held by getty/3926:
 #0: ffff88802c00e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900026362e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:7/4216:
 #0: ffff88802aaab138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000316fd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd8/0x16f0 net/ipv6/addrconf.c:4113
4 locks held by udevd/4254:
 #0: ffff888061a28668 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xae/0xd10 fs/seq_file.c:182
 #1: ffff8880613bf888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x50/0x3b0 fs/kernfs/file.c:112
 #2: ffff8880649303a8 (kn->active#32){++++}-{0:0}, at: kernfs_seq_start+0x6f/0x3b0 fs/kernfs/file.c:113
 #3: ffff888079a9d220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #3: ffff888079a9d220 (&dev->mutex){....}-{3:3}, at: uevent_show+0x17e/0x340 drivers/base/core.c:2408
6 locks held by kworker/0:15/4512:
 #0: ffff8881415a4538 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000338fd20 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff888024374220 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:760 [inline]
 #2: ffff888024374220 (&dev->mutex){....}-{3:3}, at: hub_event+0x208/0x54c0 drivers/usb/core/hub.c:5781
 #3: ffff8880243775c0 (&port_dev->status_lock){+.+.}-{3:3}, at: usb_lock_port drivers/usb/core/hub.c:3138 [inline]
 #3: ffff8880243775c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5363 [inline]
 #3: ffff8880243775c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5607 [inline]
 #3: ffff8880243775c0 (&port_dev->status_lock){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5753 [inline]
 #3: ffff8880243775c0 (&port_dev->status_lock){+.+.}-{3:3}, at: hub_event+0x2238/0x54c0 drivers/usb/core/hub.c:5835
 #4: ffff888023dc2e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect drivers/usb/core/hub.c:5364 [inline]
 #4: ffff888023dc2e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_port_connect_change drivers/usb/core/hub.c:5607 [inline]
 #4: ffff888023dc2e68 (hcd->address0_mutex){+.+.}-{3:3}, at: port_event drivers/usb/core/hub.c:5753 [inline]
 #4: ffff888023dc2e68 (hcd->address0_mutex){+.+.}-{3:3}, at: hub_event+0x2260/0x54c0 drivers/usb/core/hub.c:5835
 #5: ffffffff8d5aa530 (ehci_cf_port_reset_rwsem){.+.+}-{3:3}, at: hub_port_reset+0x1f4/0x1dd0 drivers/usb/core/hub.c:3000
2 locks held by kworker/1:15/5495:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000345fd20 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
3 locks held by kworker/1:17/5498:
 #0: ffff88802aaab138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc9000302fd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xd8/0x16f0 net/ipv6/addrconf.c:4113
2 locks held by kworker/u4:15/5811:
1 lock held by syz-executor/7913:
 #0: ffffffff8cb23aa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:322 [inline]
 #0: ffffffff8cb23aa8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x350/0x740 kernel/rcu/tree_exp.h:845
1 lock held by syz-executor/8002:
 #0: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8dc43ac8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x956/0xef0 net/core/rtnetlink.c:5644

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:369
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 5495 Comm: kworker/1:15 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: events nsim_dev_trap_report_work
RIP: 0010:memset+0x2d/0x40 mm/kasan/shadow.c:47
Code: 53 48 89 d3 41 89 f6 48 89 fd 48 8b 4c 24 18 48 89 d6 ba 01 00 00 00 e8 31 ef ff ff 84 c0 74 12 48 89 ef 44 89 f6 48 89 da 5b <41> 5e 5d e9 6b 24 72 02 31 c0 5b 41 5e 5d c3 0f 1f 40 00 41 57 41
RSP: 0018:ffffc9000345f5f0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffffc9000345f710 RCX: ffffffff8138c4b8
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc9000345f710
RBP: ffffc9000345f710 R08: dffffc0000000000 R09: fffff5200068bee4
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff1d183dc
R13: 1ffffffff1d183dc R14: 0000000000000000 R15: ffffc9000345f6c0
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005645e7635131 CR3: 000000001ea7d000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unwind_next_frame+0xbc8/0x1fa0 arch/x86/kernel/unwind_orc.c:547
 arch_stack_walk+0x10d/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x113/0x1c0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 kmem_cache_alloc_node+0x121/0x2c0 mm/slub.c:3256
 __alloc_skb+0xdd/0x590 net/core/skbuff.c:415
 alloc_skb include/linux/skbuff.h:1162 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:664 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:721 [inline]
 nsim_dev_trap_report_work+0x25e/0xab0 drivers/net/netdevsim/dev.c:762
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>