INFO: task syz.6.8211:23590 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.8211 state:D stack:26680 pid:23590 tgid:23589 ppid:21914 task_flags:0x400140 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
nfsd_nl_threads_set_doit+0x2cb/0x960 fs/nfsd/nfsctl.c:1629
genl_family_rcv_msg_doit+0x215/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x60e/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x843/0xa10 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x219/0x270 net/socket.c:729
____sys_sendmsg+0x508/0x820 net/socket.c:2614
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
__sys_sendmsg net/socket.c:2700 [inline]
__do_sys_sendmsg net/socket.c:2705 [inline]
__se_sys_sendmsg net/socket.c:2703 [inline]
__x64_sys_sendmsg+0x1a1/0x260 net/socket.c:2703
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe5ae67eba9
RSP: 002b:00007fe5ac8de038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe5ae8c5fa0 RCX: 00007fe5ae67eba9
RDX: 0000000004000000 RSI: 0000200000000780 RDI: 0000000000000003
RBP: 00007fe5ae701e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe5ae8c6038 R14: 00007fe5ae8c5fa0 R15: 00007ffd4ed96428
INFO: task syz.3.8220:23610 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.8220 state:D stack:25960 pid:23610 tgid:23609 ppid:5844 task_flags:0x400040 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
rt_mutex_slowlock_block+0x5ba/0x6d0 kernel/locking/rtmutex.c:1647
__rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline]
rt_mutex_slowlock+0x2b1/0x6e0 kernel/locking/rtmutex.c:1800
__rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:536 [inline]
mutex_lock_nested+0x16a/0x1d0 kernel/locking/rtmutex_api.c:547
nfsd_nl_rpc_status_get_dumpit+0xd9/0x12c0 fs/nfsd/nfsctl.c:1516
genl_dumpit+0x10b/0x1b0 net/netlink/genetlink.c:1027
netlink_dump+0x6e4/0xe90 net/netlink/af_netlink.c:2327
__netlink_dump_start+0x5cb/0x7e0 net/netlink/af_netlink.c:2442
genl_family_rcv_msg_dumpit+0x1e7/0x2c0 net/netlink/genetlink.c:1076
genl_family_rcv_msg net/netlink/genetlink.c:1192 [inline]
genl_rcv_msg+0x5da/0x790 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x205/0x470 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x843/0xa10 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x219/0x270 net/socket.c:729
____sys_sendmsg+0x508/0x820 net/socket.c:2614
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668
__sys_sendmsg net/socket.c:2700 [inline]
__do_sys_sendmsg net/socket.c:2705 [inline]
__se_sys_sendmsg net/socket.c:2703 [inline]
__x64_sys_sendmsg+0x1a1/0x260 net/socket.c:2703
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff183daeba9
RSP: 002b:00007ff182016038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007ff183ff5fa0 RCX: 00007ff183daeba9
RDX: 0000000000000000 RSI: 0000200000000180 RDI: 0000000000000003
RBP: 00007ff183e31e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff183ff6038 R14: 00007ff183ff5fa0 R15: 00007ffc34ee7218
Showing all locks held in the system:
3 locks held by kworker/0:0/9:
#0: ffff8880199bf138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff8880199bf138 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900000e7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900000e7bc0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888145b50188 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline]
#2: ffff888145b50188 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
4 locks held by pr/legacy/17:
2 locks held by kdevtmpfs/33:
1 lock held by khungtaskd/39:
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8d80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by acpid/5192:
#0: ffff88804adee148 (&evdev->mutex){+.+.}-{4:4}, at: evdev_open_device drivers/input/evdev.c:384 [inline]
#0: ffff88804adee148 (&evdev->mutex){+.+.}-{4:4}, at: evdev_open+0x2df/0x5b0 drivers/input/evdev.c:478
#1: ffff888061f682f0 (&dev->mutex#2){+.+.}-{4:4}, at: class_mutex_intr_constructor include/linux/mutex.h:230 [inline]
#1: ffff888061f682f0 (&dev->mutex#2){+.+.}-{4:4}, at: input_open_device+0x53/0x390 drivers/input/input.c:582
1 lock held by klogd/5196:
#0: ffff8880b883f8c8 ((&c->lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#0: ffff8880b883f8c8 ((&c->lock)){+.+.}-{3:3}, at: ___slab_alloc+0x25f/0xdc0 mm/slub.c:3773
1 lock held by udevd/5207:
2 locks held by getty/5594:
#0: ffff88823bf7e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5846:
6 locks held by kworker/1:7/6291:
4 locks held by syz-executor/15895:
3 locks held by kworker/u8:9/16433:
2 locks held by syz.0.7224/21421:
#0: ffffffff8ed39580 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8dc7ca18 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x134/0x1660 fs/nfsd/nfsctl.c:1919
2 locks held by syz.6.8211/23590:
#0: ffffffff8ed39580 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8dc7ca18 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x2cb/0x960 fs/nfsd/nfsctl.c:1629
3 locks held by syz.3.8220/23610:
#0: ffffffff8ed39580 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffff888035944910 (nlk_cb_mutex-GENERIC){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2406
#2: ffffffff8dc7ca18 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_rpc_status_get_dumpit+0xd9/0x12c0 fs/nfsd/nfsctl.c:1516
4 locks held by syz.8.10010/27317:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 39 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5207 Comm: udevd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:751
Code: 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 65 ff 05 70 18 51 10 e8 1b f3 51 09 <89> c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd 10
RSP: 0018:ffffc90003c8f990 EFLAGS: 00000282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 8574e6a7349cf500
RDX: 0000000000000000 RSI: ffffffff8b6212e0 RDI: ffffffff8b6212a0
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed102866a6d3 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffff888143353690 R15: ffff8881433535a0
FS: 00007f29d07c6880(0000) GS:ffff8881268bd000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c383e52 CR3: 0000000036a84000 CR4: 00000000003526f0
Call Trace:
rcu_read_lock_held_common kernel/rcu/update.c:109 [inline]
rcu_read_lock_held+0x15/0x50 kernel/rcu/update.c:349
kernfs_root+0xf6/0x230 fs/kernfs/kernfs-internal.h:76
kernfs_root_is_locked fs/kernfs/kernfs-internal.h:109 [inline]
kernfs_parent+0x51/0x190 fs/kernfs/kernfs-internal.h:133
kernfs_dop_revalidate+0x265/0x5d0 fs/kernfs/dir.c:1186
d_revalidate fs/namei.c:929 [inline]
lookup_fast+0x250/0x5b0 fs/namei.c:-1
walk_component fs/namei.c:2125 [inline]
link_path_walk+0x642/0xea0 fs/namei.c:2497
path_lookupat+0x97/0x430 fs/namei.c:2653
filename_lookup+0x212/0x570 fs/namei.c:2683
do_readlinkat+0xd9/0x500 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f29d09223a7
Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 8a 20 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 21 ba 0d 00 f7 d8 64 89 02 48
RSP: 002b:00007ffd1cd3c668 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffd1cd3cb40 RCX: 00007f29d09223a7
RDX: 0000000000000400 RSI: 00007ffd1cd3c670 RDI: 00007ffd1cd3cb40
RBP: 00007ffd1cd3c670 R08: 0000558d502078e4 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 00000000000000fe R14: 0000558d308fdbe0 R15: 00007ffd1cd3d6f0