syzbot

INFO: task syz.3.20:4526 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D stack:26688 pid:4526  ppid:4404   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 rwsem_down_read_slowpath+0x4f4/0x840 kernel/locking/rwsem.c:1094
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x94/0x2d0 kernel/locking/rwsem.c:1522
 iterate_supers+0xa4/0x1d0 fs/super.c:755
 ksys_sync+0x91/0x150 fs/sync.c:102
 __ia32_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f638678f749
RSP: 002b:00007ffeed155f48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f63869e5fa0 RCX: 00007f638678f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f63869e5fa0 R14: 00007f63869e5fa0 R15: 0000000000000000
 </TASK>
INFO: task syz.4.21:4527 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:26688 pid:4527  ppid:4412   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 rwsem_down_read_slowpath+0x4f4/0x840 kernel/locking/rwsem.c:1094
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x94/0x2d0 kernel/locking/rwsem.c:1522
 iterate_supers+0xa4/0x1d0 fs/super.c:755
 ksys_sync+0x91/0x150 fs/sync.c:102
 __ia32_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e3b18f749
RSP: 002b:00007fff640e0f18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f8e3b3e5fa0 RCX: 00007f8e3b18f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e3b3e5fa0 R14: 00007f8e3b3e5fa0 R15: 0000000000000000
 </TASK>
INFO: task syz.2.19:4528 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:26672 pid:4528  ppid:4402   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6696
 rwsem_down_read_slowpath+0x4f4/0x840 kernel/locking/rwsem.c:1094
 __down_read_common kernel/locking/rwsem.c:1261 [inline]
 __down_read kernel/locking/rwsem.c:1274 [inline]
 down_read+0x94/0x2d0 kernel/locking/rwsem.c:1522
 iterate_supers+0xa4/0x1d0 fs/super.c:755
 ksys_sync+0x91/0x150 fs/sync.c:102
 __ia32_sys_sync+0xa/0x10 fs/sync.c:113
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4ada78f749
RSP: 002b:00007ffed82bf398 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f4ada9e5fa0 RCX: 00007f4ada78f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ada9e5fa0 R14: 00007f4ada9e5fa0 R15: 0000000000000000
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8c92bab0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8c92c2d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/27:
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8c92b120 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
3 locks held by kworker/u4:4/57:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90001587d00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263
2 locks held by kworker/0:3/2183:
 #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc90005e67d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4024:
 #0: ffff88814de98098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41b/0x1380 drivers/tty/n_tty.c:2198
3 locks held by kworker/1:5/4393:
 #0: ffff88814cead138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #1: ffffc900032a7d00 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a1/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xc4/0x14d0 net/ipv6/addrconf.c:4131
1 lock held by syz.0.17/4460:
 #0: ffff88807852e0e0 (&type->s_umount_key#70/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228
1 lock held by syz.1.18/4462:
 #0: ffff8880238d40e0 (&type->s_umount_key#70/1){+.+.}-{3:3}, at: alloc_super+0x1fa/0x930 fs/super.c:228
1 lock held by syz.3.20/4526:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.4.21/4527:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.2.19/4528:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.5.22/4579:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.6.23/4580:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.7.24/4656:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.9.26/4658:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.8.25/4659:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.0.27/4704:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.1.28/4705:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.2.29/4766:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.3.30/4767:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.4.31/4768:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.5.32/4808:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.6.33/4819:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.7.34/4866:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.8.36/4898:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.9.35/4899:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.0.37/4926:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.1.38/4937:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.2.39/4957:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.3.41/5012:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.4.40/5013:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.5.42/5049:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.6.43/5065:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.7.44/5085:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.9.45/5147:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.8.46/5148:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.0.47/5182:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.1.48/5183:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.2.49/5194:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz-executor/5242:
 #0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6147
1 lock held by syz-executor/5246:
 #0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline]
 #0: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x740/0xed0 net/core/rtnetlink.c:6147
1 lock held by syz.3.51/5248:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
1 lock held by syz.4.50/5253:
 #0: ffff88807852e0e0 (&type->s_umount_key#71){.+.+}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:755
8 locks held by syz-executor/5277:
 #0: ffff88807ddb6460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x256/0x960 fs/read_write.c:580
 #1: ffff888045dd0088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343
 #2: ffff888145327ae8 (kn->active#59){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff888145327ae8 (kn->active#59){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344
 #3: ffffffff8d44d168 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xce/0x360 drivers/net/netdevsim/bus.c:209
 #4: ffff8880590de0e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline]
 #4: ffff8880590de0e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline]
 #4: ffff8880590de0e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb2/0x850 drivers/base/dd.c:1283
 #5: ffff8880590db2f8 (&devlink->lock_key#29){+.+.}-{3:3}, at: nsim_drv_remove+0x54/0x160 drivers/net/netdevsim/dev.c:1677
 #6: ffffffff8db3b3a8 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3b/0x150 drivers/net/netdevsim/netdev.c:381
 #7: ffffffff8c930df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #7: ffffffff8c930df8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x455/0x830 kernel/rcu/tree_exp.h:962

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3f4/0x470 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue:  0x0 (phy7)
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x4/0x60 kernel/kcov.c:215
Code: 00 00 00 00 00 90 53 48 89 fb e8 17 00 00 00 48 8b 3d 90 30 7e 0c 48 89 de 5b e9 47 68 4f 00 00 00 cc cc 00 00 cc 48 8b 04 24 <65> 48 8b 0d 64 8f 81 7e 65 8b 15 65 8f 81 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900000e7c00 EFLAGS: 00000002
RAX: ffffffff815420a7 RBX: ffff8880694a8400 RCX: 0000000000000000
RDX: ffff88813fe80000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: ffff888017618a10
R10: ffffed1002ec3145 R11: 1ffff11002ec3142 R12: 00000000ffffffff
R13: dffffc0000000000 R14: 1ffff1100d295082 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fad9ad60370 CR3: 000000000c68e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 put_pwq kernel/workqueue.c:1129 [inline]
 pwq_dec_nr_in_flight+0x1a7/0x450 kernel/workqueue.c:1228
 process_one_work+0xb7b/0x1160 kernel/workqueue.c:2335
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>