INFO: task syz.0.9174:8018 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.9174 state:D stack:28184 pid:8018 tgid:8017 ppid:7689 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5583 [inline]
__schedule+0x125e/0x6990 kernel/sched/core.c:7382
__schedule_loop kernel/sched/core.c:7459 [inline]
schedule+0xdd/0x2c0 kernel/sched/core.c:7474
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7531
__mutex_lock_common kernel/locking/mutex.c:726 [inline]
__mutex_lock+0xcca/0x1c10 kernel/locking/mutex.c:821
write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
nfsctl_transaction_write+0x106/0x1a0 fs/nfsd/nfsctl.c:114
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:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5b0119f559
RSP: 002b:00007f5b0209c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5b01425fa0 RCX: 00007f5b0119f559
RDX: 0000000000000001 RSI: 00002000000001c0 RDI: 0000000000000004
RBP: 00007f5b01236b20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5b01426038 R14: 00007f5b01425fa0 R15: 00007ffe3a4c4d08
Showing all locks held in the system:
locks held by khungtaskd/31: 1, last CPU#0:
#0: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6871
locks held by getty/5367: 2, on CPU#1:
#0: ffff88802b4510a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc9000322e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x1540 drivers/tty/n_tty.c:2211
locks held by kworker/u8:18/27966: 4, last CPU#1:
#0: ffff88803575c148 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work+0x1461/0x1b10 kernel/workqueue.c:3470
#1: ffffc9000374fd08 ((work_completion)(&(&forw_packet_aggr->delayed_work)->work)){+.+.}-{0:0}, at: process_one_work+0xa2c/0x1b10 kernel/workqueue.c:3471
#2: ffff888066ff0dd8 (&hash->list_locks[i]){+...}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:353 [inline]
#2: ffff888066ff0dd8 (&hash->list_locks[i]){+...}-{3:3}, at: __batadv_dat_purge.part.0+0xf6/0x3c0 net/batman-adv/distributed-arp-table.c:240
#3: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8ffeb420 (rcu_read_lock){....}-{1:3}, at: batadv_iv_ogm_schedule_buff+0xdcf/0x15d0 net/batman-adv/bat_iv_ogm.c:968
locks held by syz.1.9125/7913: 2, on CPU#1:
#0: ffffffff91fb9d08 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff904975c0 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x1a3/0x1dc0 fs/nfsd/nfsctl.c:2057
locks held by syz.0.9174/8018: 3, on CPU#1:
#0: ffff8880663f5cf0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1408
#1: ffff88802c354460 (sb_writers#26){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff904975c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
locks held by syz.2.9246/8314: 3, on CPU#1:
#0: ffff8880678ee7f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1408
#1: ffff88807a594460 (sb_writers#26){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739
#2: ffffffff904975c0 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xa5/0xcc0 fs/nfsd/nfsctl.c:867
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026
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:123
nmi_trigger_cpumask_backtrace+0x21f/0x2a0 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 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: 27966 Comm: kworker/u8:18 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/15/2026
Workqueue: bat_events batadv_bla_periodic_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline]
RIP: 0010:lock_release kernel/locking/lockdep.c:5966 [inline]
RIP: 0010:lock_release+0x17d/0x310 kernel/locking/lockdep.c:5950
Code: 74 0e 8b 05 45 3e 80 10 85 c0 0f 84 83 01 00 00 90 48 c7 c7 37 48 5f 8e e8 d0 15 fe 09 b8 ff ff ff ff 65 0f c1 05 9b 63 ce 13 <83> f8 01 0f 85 27 01 00 00 9c 58 f6 c4 02 0f 85 12 01 00 00 41 f7
RSP: 0018:ffffc90000a080d0 EFLAGS: 00000057
RAX: 0000000000000001 RBX: ffffffff8ffeb420 RCX: ffffc90000a080dc
RDX: 0000000000000101 RSI: ffffffff8e5f4837 RDI: ffffffff8c831680
RBP: ffffffff81bb1d4e R08: 0000000000000001 R09: 0000000000000007
R10: 0000000000000200 R11: 000000000009b603 R12: ffff888038c28000
R13: ffffc90000a08188 R14: 0000000000000202 R15: 0000000000000005
FS: 0000000000000000(0000) GS:ffff8881225ac000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000560f5bd27960 CR3: 000000000fd96000 CR4: 00000000003526f0
Call Trace:
rcu_lock_release include/linux/rcupdate.h:319 [inline]
rcu_read_unlock include/linux/rcupdate.h:880 [inline]
class_rcu_destructor include/linux/rcupdate.h:1216 [inline]
unwind_next_frame+0x3c3/0x2090 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:351 [inline]
__kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:377
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4720 [inline]
slab_alloc_node mm/slub.c:5033 [inline]
kmem_cache_alloc_noprof+0x269/0x6a0 mm/slub.c:5047
skb_clone+0x187/0x3f0 net/core/skbuff.c:2110
deliver_clone net/bridge/br_forward.c:140 [inline]
maybe_deliver+0x3cc/0x590 net/bridge/br_forward.c:212
br_flood_port+0x32a/0x540 net/bridge/br_forward.c:285
br_flood+0x59a/0x810 net/bridge/br_forward.c:345
br_handle_frame_finish+0x1218/0x1ff0 net/bridge/br_input.c:231
nf_hook_bridge_pre net/bridge/br_input.c:315 [inline]
br_handle_frame+0x7db/0x1660 net/bridge/br_input.c:453
__netif_receive_skb_core.constprop.0+0x736/0x35a0 net/core/dev.c:6292
__netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6403
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6518
process_backlog+0x487/0x1600 net/core/dev.c:6869
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7938
napi_poll net/core/dev.c:8001 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:8158
handle_softirqs+0x216/0xa20 kernel/softirq.c:669
do_softirq kernel/softirq.c:569 [inline]
do_softirq+0xaf/0xf0 kernel/softirq.c:556
__local_bh_enable_ip+0xff/0x120 kernel/softirq.c:473
local_bh_enable include/linux/bottom_half.h:33 [inline]
netif_rx net/core/dev.c:5978 [inline]
netif_rx+0x93/0xb0 net/core/dev.c:5967
batadv_bla_send_claim+0x4dd/0x1160 net/batman-adv/bridge_loop_avoidance.c:441
batadv_bla_send_announce+0x130/0x190 net/batman-adv/bridge_loop_avoidance.c:675
batadv_bla_periodic_work+0x428/0xa10 net/batman-adv/bridge_loop_avoidance.c:1530
process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495
process_scheduled_works kernel/workqueue.c:3578 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659
kthread+0x373/0x450 kernel/kthread.c:436
ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245