INFO: task syz.0.3430:23329 blocked for more than 143 seconds.
Tainted: G U L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.3430 state:D stack:27464 pid:23329 tgid:23328 ppid:17195 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1023/0x6000 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7004
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1736
genl_family_rcv_msg_doit+0x214/0x300 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x560/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa54/0xc30 net/socket.c:2592
___sys_sendmsg+0x190/0x1e0 net/socket.c:2646
__sys_sendmsg+0x170/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8db019bf79
RSP: 002b:00007f8db10bf028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8db0415fa0 RCX: 00007f8db019bf79
RDX: 0000000004044880 RSI: 00002000000004c0 RDI: 0000000000000004
RBP: 00007f8db02327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8db0416038 R14: 00007f8db0415fa0 R15: 00007ffc1167d7b8
Showing all locks held in the system:
1 lock held by khungtaskd/30:
#0: ffffffff8e5e6e60 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e5e6e60 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e5e6e60 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
5 locks held by kworker/u10:30/13775:
#0: ffff88801c2a7148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x11ae/0x1840 kernel/workqueue.c:3232
#1: ffffc9000b4dfd08 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x927/0x1840 kernel/workqueue.c:3233
#2: ffffffff903e86f0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xab/0x830 net/core/net_namespace.c:670
#3: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: ops_exit_rtnl_list net/core/net_namespace.c:173 [inline]
#3: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: ops_undo_list+0x7ec/0xab0 net/core/net_namespace.c:248
#4: ffffffff8e5f2a78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
2 locks held by syz.2.3310/22685:
#0: ffffffff904aded0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea4f2e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
2 locks held by syz.0.3430/23329:
#0: ffffffff904aded0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea4f2e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_set_doit+0xc4/0x7a0 fs/nfsd/nfsctl.c:1736
2 locks held by syz.6.3494/23967:
#0: ffffffff904aded0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea4f2e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
1 lock held by syz.4.3614/24751:
#0: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3436
2 locks held by syz.8.3617/24756:
#0: ffffffff904aded0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea4f2e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
2 locks held by syz.7.3756/25371:
#0: ffffffff904aded0 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8ea4f2e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1596
1 lock held by syz-executor/25595:
#0: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff90401028 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3436
4 locks held by syz.9.3916/26301:
1 lock held by syz.9.3916/26340:
#0: ffff8880334b8d38 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1255
1 lock held by syz.5.3922/26327:
#0: ffff8880b843b0e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:655 [inline]
#0: ffff8880b843b0e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x88/0x140 kernel/sched/core.c:639
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 30 Comm: khungtaskd Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xcc3/0xfe0 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:467
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 26301 Comm: syz.9.3916 Tainted: G U L syzkaller #0 PREEMPT(full)
Tainted: [U]=USER, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:313
Code: 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff
RSP: 0018:ffffc900044774f8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffff2afc462000 RCX: ffffc90022333000
RDX: 0000000000080000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88813fe11310 R08: 0000000000000006 R09: ffffffff80000000
R10: ffffff2afc462000 R11: 2020202020202020 R12: ffffff2afc463000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff8ba48700
FS: 00007f564da616c0(0000) GS:ffff8881246b1000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000003fe000 CR3: 000000007762a000 CR4: 00000000003526f0
Call Trace:
walk_pte_range_inner+0x264/0x360 mm/pagewalk.c:51
walk_pte_range mm/pagewalk.c:81 [inline]
walk_pmd_range mm/pagewalk.c:155 [inline]
walk_pud_range mm/pagewalk.c:224 [inline]
walk_p4d_range mm/pagewalk.c:262 [inline]
walk_pgd_range+0xecb/0x1eb0 mm/pagewalk.c:303
walk_page_range_debug+0x1ca/0x370 mm/pagewalk.c:694
ptdump_walk_pgd+0x129/0x330 mm/ptdump.c:182
ptdump_walk_pgd_level_core+0x26c/0x300 arch/x86/mm/dump_pagetables.c:458
ptdump_curknl_show+0x75/0xa0 arch/x86/mm/debug_pagetables.c:19
seq_read_iter+0x32f/0x1270 fs/seq_file.c:230
seq_read+0x33b/0x4c0 fs/seq_file.c:162
full_proxy_read+0x135/0x1a0 fs/debugfs/file.c:378
vfs_read+0x1e4/0xb30 fs/read_write.c:572
ksys_read+0x12a/0x250 fs/read_write.c:717
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f564cb9bf79
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f564da61028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f564ce15fa0 RCX: 00007f564cb9bf79
RDX: 0000000000001000 RSI: 0000200000000300 RDI: 0000000000000003
RBP: 00007f564cc327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f564ce16038 R14: 00007f564ce15fa0 R15: 00007ffd029d0668