syzbot

INFO: task syz.7.1485:10635 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.7.1485      state:D stack:26240 pid:10635 ppid:  9429 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6537
 rwsem_down_read_slowpath+0x528/0x990 kernel/locking/rwsem.c:1055
 __down_read_common kernel/locking/rwsem.c:1239 [inline]
 __down_read kernel/locking/rwsem.c:1252 [inline]
 down_read+0x96/0x2e0 kernel/locking/rwsem.c:1500
 iterate_supers+0xa4/0x1d0 fs/super.c:716
 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:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f2254599749
RSP: 002b:00007f2252800038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2
RAX: ffffffffffffffda RBX: 00007f22547effa0 RCX: 00007f2254599749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f22547effa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f22547f0038 R14: 00007f22547effa0 R15: 00007ffe667c9be8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c720 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
3 locks held by kworker/u4:1/144:
2 locks held by getty/3949:
 #0: ffff88802c2d9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
3 locks held by kworker/0:4/4232:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc9000311fd00 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffff88807ecf2400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_trap_report_work+0x56/0xb40 drivers/net/netdevsim/dev.c:757
3 locks held by kworker/u4:9/4348:
 #0: ffff888016879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900037efd00 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:251
4 locks held by syz.0.526/6352:
5 locks held by syz.6.1195/9254:
2 locks held by syz-executor/10076:
 #0: ffff888020a4c518 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff8881472bb468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366
7 locks held by kworker/u4:14/10432:
 #0: ffff8880169cd938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900032cfd00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8d226b10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x132/0xb80 net/core/net_namespace.c:589
 #3: ffffffff8d257e48 (devlink_mutex){+.+.}-{3:3}, at: devlink_pernet_pre_exit+0x97/0x300 net/core/devlink.c:11534
 #4: ffff88807ecf1658 (&nsim_bus_dev->nsim_bus_reload_lock){+.+.}-{3:3}, at: nsim_dev_reload_down+0x57/0x160 drivers/net/netdevsim/dev.c:870
 #5: ffff88807ecf2400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1359 [inline]
 #5: ffff88807ecf2400 (&nsim_dev->port_list_lock){+.+.}-{3:3}, at: nsim_dev_reload_destroy+0x115/0x240 drivers/net/netdevsim/dev.c:1561
 #6: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: devlink_nl_port_fill+0x295/0x870 net/core/devlink.c:995
2 locks held by kworker/0:22/10602:
 #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90003d87d00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
1 lock held by syz.7.1485/10635:
 #0: ffff88807da000e0 (&type->s_umount_key#75){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716
1 lock held by syz.5.1542/10940:
 #0: ffff88807da000e0 (&type->s_umount_key#75){++++}-{3:3}, at: iterate_supers+0xa4/0x1d0 fs/super.c:716
3 locks held by kworker/u4:15/13126:
2 locks held by syz-executor/13646:
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #1: ffffffff8c1211a8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
1 lock held by syz.6.2089/13753:
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
 #0: ffffffff8d232788 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7a5/0xe90 net/core/rtnetlink.c:5681
1 lock held by sed/13770:

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

NMI backtrace for cpu 1
CPU: 1 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+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 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+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6352 Comm: syz.0.526 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:168 [inline]
RIP: 0010:unwind_next_frame+0x1a7/0x1d90 arch/x86/kernel/unwind_orc.c:448
Code: c1 0f 85 c8 00 00 00 48 c7 c0 00 00 00 81 49 89 ee 49 29 c6 49 c1 ee 08 8b 15 05 95 87 0a 8d 42 ff 44 39 f0 0f 86 f5 14 00 00 <44> 89 f0 4c 8d 24 85 9c 31 7c 8e 4c 89 e0 48 c1 e8 03 42 0f b6 04
RSP: 0018:ffffc9000356f7c8 EFLAGS: 00000202
RAX: 000000000008e07e RBX: ffffc9000356f888 RCX: ffffffff960b0f00
RDX: 000000000008e07f RSI: ffffffff81667a78 RDI: 0000000000000001
RBP: ffffffff81667a77 R08: ffffc9000356f950 R09: 0000000000000000
R10: fffff520006adf1d R11: 1ffff920006adf1b R12: ffffffff81667a78
R13: dffffc0000000000 R14: 000000000000667a R15: ffffc9000356f8d0
FS:  00007f6cf402e6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f203a019198 CR3: 0000000060514000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 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_kmalloc mm/kasan/common.c:513 [inline]
 __kasan_kmalloc+0xb5/0xf0 mm/kasan/common.c:522
 kmalloc include/linux/slab.h:607 [inline]
 io_cqring_event_overflow+0x59/0x310 io_uring/io_uring.c:1779
 io_poll_check_events+0x461/0x810 io_uring/io_uring.c:5668
 io_poll_task_func+0x40/0x280 io_uring/io_uring.c:5697
 tctx_task_work+0x2d3/0x5d0 io_uring/io_uring.c:2209
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_signal include/linux/tracehook.h:214 [inline]
 handle_signal_work kernel/entry/common.c:152 [inline]
 exit_to_user_mode_loop+0x8d/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f6cf5dc7749
Code: Unable to access opcode bytes at RIP 0x7f6cf5dc771f.
RSP: 002b:00007f6cf402e038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000000001 RBX: 00007f6cf601dfa0 RCX: 00007f6cf5dc7749
RDX: 0000000000000000 RSI: 0000000000007277 RDI: 0000000000000003
RBP: 00007f6cf5e4bf91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000e R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6cf601e038 R14: 00007f6cf601dfa0 R15: 00007ffee3f73908
 </TASK>