INFO: task syz.4.5300:18450 blocked for more than 143 seconds.
Tainted: G S L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.5300 state:D stack:27032 pid:18450 tgid:18449 ppid:5610 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5510 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7234
__schedule_loop kernel/sched/core.c:7311 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7326
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7383
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xccc/0x1bd0 kernel/locking/mutex.c:821
write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:112
vfs_write+0x2aa/0x1050 fs/read_write.c:685
ksys_write+0x12a/0x250 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd706b9e019
RSP: 002b:00007fd707a95028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fd706e25fa0 RCX: 00007fd706b9e019
RDX: 0000000000000006 RSI: 00002000000000a0 RDI: 0000000000000003
RBP: 00007fd706c3500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd706e26038 R14: 00007fd706e25fa0 R15: 00007fff67289778
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline]
#0: ffffffff8ebe8200 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
2 locks held by getty/5360:
#0: ffff8880373d80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc900032332e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211
2 locks held by syz-executor/5611:
#0: ffff8880673740d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880673740d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880673740d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff8880673740d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by kworker/1:7/5750:
#0: ffff88801bc0f140 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297
#1: ffffc9000459fd08 ((work_completion)(&m->mpeg_thread)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298
2 locks held by syz-executor/10251:
#0: ffff88807a82c0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807a82c0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807a82c0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff88807a82c0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
3 locks held by syz.7.5003/17785:
#0: ffff88807622e9b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888051298450 (sb_writers#25){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x278/0x570 fs/nfsd/nfsctl.c:432
3 locks held by syz.4.5300/18450:
#0: ffff88801d68e9b0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259
#1: ffff888055496450 (sb_writers#25){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:860
2 locks held by syz-executor/18889:
#0: ffff88804f4fa0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88804f4fa0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88804f4fa0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff88804f4fa0d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz-executor/18973:
#0: ffff8880278160d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880278160d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff8880278160d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super fs/super.c:509 [inline]
#0: ffff8880278160d8 (&type->s_umount_key#86){+.+.}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:506
#1: ffffffff8f072880 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:576
2 locks held by syz.8.7541/24381:
#0: ffffffff90aa0200 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline]
#0: ffffffff90aa0200 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline]
#0: ffffffff90aa0200 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8bb/0x2380 net/core/rtnetlink.c:4158
#1: ffffffff8ebf3ca8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x27f/0x3c0 kernel/rcu/tree_exp.h:311
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G S L syzkaller #0 PREEMPT(full)
Tainted: [S]=CPU_OUT_OF_SPEC, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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:122
nmi_trigger_cpumask_backtrace+0x21c/0x2a0 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xcb1/0x1030 kernel/hung_task.c:561
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
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: 24381 Comm: syz.8.7541 Tainted: G S L syzkaller #0 PREEMPT(full)
Tainted: [S]=CPU_OUT_OF_SPEC, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:get_current arch/x86/include/asm/current.h:23 [inline]
RIP: 0010:write_comp_data+0x10/0x90 kernel/kcov.c:245
Code: 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 99 22 5a 12 49 89 f8 49 89 f1 49 89 d2 <65> 48 8b 3d 70 22 5a 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00
RSP: 0018:ffffc9000345e3f8 EFLAGS: 00000202
RAX: 0000000000000202 RBX: 0000000000000075 RCX: ffffffff8bb77e79
RDX: 0000000000000075 RSI: 000000000000002e RDI: 0000000000000001
RBP: ffffc9000345e4a0 R08: 0000000000000001 R09: 000000000000002e
R10: 0000000000000075 R11: 000000000008cdd8 R12: 0000000000000075
R13: ffffffff8bd08d03 R14: ffffc9000345e530 R15: 0000000000000045
FS: 00007fba965856c0(0000) GS:ffff888123dd8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f80b49f14b8 CR3: 000000009bdee000 CR4: 00000000003526f0
DR0: 0000000002000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
format_decode+0x3c9/0xdd0 lib/vsprintf.c:2740
vsnprintf+0x1c0/0x1300 lib/vsprintf.c:2887
snprintf+0xc7/0x100 lib/vsprintf.c:3043
print_caller kernel/printk/printk.c:1368 [inline]
info_print_prefix+0x134/0x350 kernel/printk/printk.c:1387
record_print_text+0x143/0x3c0 kernel/printk/printk.c:1434
printk_get_next_message+0x2d1/0x6c0 kernel/printk/printk.c:3072
console_emit_next_record kernel/printk/printk.c:3137 [inline]
console_flush_one_record+0x67c/0xe50 kernel/printk/printk.c:3269
console_flush_all kernel/printk/printk.c:3343 [inline]
__console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
console_unlock+0x103/0x260 kernel/printk/printk.c:3413
vprintk_emit+0x407/0x6b0 kernel/printk/printk.c:2479
_printk+0xcf/0x110 kernel/printk/printk.c:2504
br_set_state+0x386/0x620 net/bridge/br_stp.c:57
br_stp_disable_port+0x65/0x1e0 net/bridge/br_stp_if.c:106
br_stp_disable_bridge+0xca/0x180 net/bridge/br_stp_if.c:76
br_dev_stop+0x26/0x1b0 net/bridge/br_device.c:193
__dev_close_many+0x312/0x710 net/core/dev.c:1776
__dev_close net/core/dev.c:1789 [inline]
__dev_change_flags+0x307/0x850 net/core/dev.c:9758
netif_change_flags+0x8d/0x160 net/core/dev.c:9823
do_setlink.isra.0+0x1ac4/0x3e60 net/core/rtnetlink.c:3215
rtnl_group_changelink net/core/rtnetlink.c:3863 [inline]
__rtnl_newlink net/core/rtnetlink.c:4031 [inline]
rtnl_newlink+0x1b7e/0x2380 net/core/rtnetlink.c:4159
rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:7076
netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2556
netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1345
netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1900
sock_sendmsg_nosec net/socket.c:775 [inline]
__sock_sendmsg net/socket.c:790 [inline]
____sys_sendmsg+0xa4d/0xbe0 net/socket.c:2684
___sys_sendmsg+0x190/0x1e0 net/socket.c:2738
__sys_sendmsg+0x160/0x210 net/socket.c:2770
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fba9579e019
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:00007fba96585028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fba95a25fa0 RCX: 00007fba9579e019
RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000004
RBP: 00007fba9583500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fba95a26038 R14: 00007fba95a25fa0 R15: 00007ffe5c29a3f8