syzbot

INFO: task syz.4.53:6026 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.53        state:D stack:21608 pid:6026  tgid:6025  ppid:5601   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5510 [inline]
 __schedule+0x16dc/0x5500 kernel/sched/core.c:7234
 __schedule_loop kernel/sched/core.c:7311 [inline]
 schedule+0x164/0x2b0 kernel/sched/core.c:7326
 percpu_rwsem_wait+0x32d/0x4a0 kernel/locking/percpu-rwsem.c:164
 __percpu_down_read+0xf8/0x140 kernel/locking/percpu-rwsem.c:180
 percpu_down_read_internal include/linux/percpu-rwsem.h:67 [inline]
 percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
 __sb_start_write include/linux/fs/super.h:19 [inline]
 sb_start_write+0x18e/0x1c0 include/linux/fs/super.h:125
 mnt_want_write+0x41/0x90 fs/namespace.c:494
 path_openat+0x3095/0x3850 fs/namei.c:4854
 do_file_open+0x23e/0x4a0 fs/namei.c:4892
 do_sys_openat2+0x115/0x200 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1385
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbd0c2cde99
RSP: 002b:00007fbd0a526028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fbd0c555fa0 RCX: 00007fbd0c2cde99
RDX: 0000000000531881 RSI: 0000200000000240 RDI: ffffffffffffff9c
RBP: 00007fbd0c363eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbd0c556038 R14: 00007fbd0c555fa0 R15: 00007ffc35699eb8
 </TASK>

Showing all locks held in the system:
5 locks held by kworker/u8:1/13:
 #0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801aea0938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffffffff8f5a2a00 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673
 #3: ffff888039bd9978 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_destruct+0x116/0x310 drivers/net/wireguard/device.c:249
 #4: ffffffff8e1c91b0 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x530 kernel/rcu/tree.c:3857
1 lock held by khungtaskd/38:
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
 #0: ffffffff8e1c3000 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u8:4/66:
3 locks held by kworker/u8:14/2186:
 #0: ffff8880605e4938 ((wq_completion)loop5){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff8880605e4938 ((wq_completion)loop5){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90007ed7c40 ((work_completion)(&worker->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90007ed7c40 ((work_completion)(&worker->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffff88802683e160 (&lo->lo_work_lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:96 [inline]
 #2: ffff88802683e160 (&lo->lo_work_lock){+.+.}-{3:3}, at: loop_process_work+0x125/0x11d0 drivers/block/loop.c:1945
8 locks held by kworker/u8:16/3336:
5 locks held by kworker/u8:17/3406:
2 locks held by getty/5355:
 #0: ffff888035e2e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
6 locks held by udevd/5591:
1 lock held by syz-executor/5606:
2 locks held by kworker/1:5/5733:
1 lock held by syz.4.53/6026:
 #0: ffff888066c66500 (sb_writers#20){++++}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:494
1 lock held by udevd/6044:
1 lock held by syz-executor/7047:
 #0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
 #0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x65e/0xdf0 net/ipv6/addrconf.c:5062
1 lock held by syz-executor/7260:
 #0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
 #0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
 #0: ffffffff8f5b15b8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a3/0x1bd0 net/core/rtnetlink.c:4158
1 lock held by syz.5.289/7583:
5 locks held by syz.5.289/7584:
1 lock held by syz.5.289/7601:
 #0: ffff88805f076100 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: inode_lock include/linux/fs.h:1024 [inline]
 #0: ffff88805f076100 (&sb->s_type->i_mutex_key#28){++++}-{4:4}, at: process_measurement+0x449/0x1c20 security/integrity/ima/ima_main.c:300
2 locks held by syz.1.293/7603:
 #0: ffff888037bcc0d0 (&type->s_umount_key#28/1){+.+.}-{4:4}, at: alloc_super fs/super.c:345 [inline]
 #0: ffff888037bcc0d0 (&type->s_umount_key#28/1){+.+.}-{4:4}, at: sget_fc+0x938/0x1910 fs/super.c:766
 #1: ffffffff8de0e9e8 (bit_wait_table + i){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #1: ffffffff8de0e9e8 (bit_wait_table + i){+.+.}-{3:3}, at: finish_wait kernel/sched/wait.c:394 [inline]
 #1: ffffffff8de0e9e8 (bit_wait_table + i){+.+.}-{3:3}, at: __wait_on_bit+0x1ec/0x2f0 kernel/sched/wait_bit.c:55

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:122
 nmi_trigger_cpumask_backtrace+0x17a/0x380 lib/nmi_backtrace.c:65
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd7/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 66 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:rt_spin_trylock+0x21b/0x2b0 kernel/locking/spinlock_rt.c:135
Code: 0f 85 99 00 00 00 66 c7 03 01 00 bf 01 00 00 00 e8 7a a1 4e f6 65 8b 05 d3 9d 58 07 85 c0 74 22 b8 01 00 00 00 48 83 c4 10 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 90 0f 0b 90 e9 71 ff
RSP: 0018:ffffc9000151f940 EFLAGS: 00000282
RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000080000001
RDX: 00000000214c5af7 RSI: ffffffff8bca6560 RDI: ffffffff8bca6520
RBP: 0000000000000001 R08: ffffffff8b45015c R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff8e1c3000 R12: dffffc0000000000
R13: ffff8880b8740840 R14: ffff8880b8740858 R15: 1ffff11003f5e478
FS:  0000000000000000(0000) GS:ffff888125d46000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1e5c8cceb8 CR3: 0000000038d8a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 alloc_from_pcs mm/slub.c:4795 [inline]
 slab_alloc_node mm/slub.c:4933 [inline]
 __do_kmalloc_node mm/slub.c:5361 [inline]
 __kmalloc_node_track_caller_noprof+0x33a/0x7c0 mm/slub.c:5497
 kmalloc_reserve net/core/skbuff.c:637 [inline]
 __alloc_skb+0x2bd/0x7a0 net/core/skbuff.c:715
 alloc_skb include/linux/skbuff.h:1384 [inline]
 nsim_dev_trap_skb_build drivers/net/netdevsim/dev.c:819 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:876 [inline]
 nsim_dev_trap_report_work+0x2b1/0xcb0 drivers/net/netdevsim/dev.c:922
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>