rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1144/1:b..l P3466/2:b..l
rcu: (detected by 1, t=10502 jiffies, g=11677, q=524 ncpus=2)
task:kworker/u4:9 state:R running task stack:24776 pid:3466 ppid:2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6866
preempt_schedule+0xab/0xc0 kernel/sched/core.c:6890
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__local_bh_enable_ip+0x13f/0x1c0 kernel/softirq.c:413
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:856 [inline]
__dev_queue_xmit+0x1449/0x35a0 net/core/dev.c:4452
dev_queue_xmit include/linux/netdevice.h:3113 [inline]
neigh_hh_output include/net/neighbour.h:527 [inline]
neigh_output include/net/neighbour.h:541 [inline]
ip6_finish_output2+0xdf5/0x1650 net/ipv6/ip6_output.c:141
dst_output include/net/dst.h:467 [inline]
NF_HOOK+0x163/0x470 include/linux/netfilter.h:304
mld_sendpack+0x7f9/0xd70 net/ipv6/mcast.c:1823
ipv6_mc_dad_complete+0x88/0x210 net/ipv6/mcast.c:2248
addrconf_dad_completed+0x6d0/0xd40 net/ipv6/addrconf.c:4304
addrconf_dad_work+0xc4e/0x14e0 net/ipv6/addrconf.c:-1
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
task:kworker/u4:7 state:R running task stack:21712 pid:1144 ppid:2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:percpu_counter_add_batch+0x235/0x280 lib/percpu_counter.c:103
Code: 4d 85 f6 75 16 e8 bb 64 35 fd eb 15 e8 b4 64 35 fd e8 3f 4b 17 06 4d 85 f6 74 ea e8 a5 64 35 fd fb 48 c7 44 24 40 0e 36 e0 45 <48> 8b 44 24 38 4a c7 04 38 00 00 00 00 66 42 c7 44 38 09 00 00 42
RSP: 0018:ffffc900047bebe0 EFLAGS: 00000293
RAX: ffffffff84502c1b RBX: 0000000000000000 RCX: ffff8880240b0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900047becd0 R08: ffffffff90d945a7 R09: 1ffffffff21b28b4
R10: dffffc0000000000 R11: fffffbfff21b28b5 R12: 1ffff110049b382c
R13: 000000000000000f R14: 0000000000000200 R15: dffffc0000000000
wb_stat_mod include/linux/backing-dev.h:67 [inline]
folio_clear_dirty_for_io+0x654/0xc30 mm/page-writeback.c:2933
mpage_submit_folio+0x7d/0x3c0 fs/ext4/inode.c:1889
mpage_map_and_submit_buffers fs/ext4/inode.c:2154 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2293 [inline]
ext4_do_writepages+0x1d01/0x38d0 fs/ext4/inode.c:2718
ext4_writepages+0x1a8/0x2f0 fs/ext4/inode.c:2807
do_writepages+0x3a2/0x600 mm/page-writeback.c:2575
__writeback_single_inode+0x153/0xee0 fs/fs-writeback.c:1635
writeback_sb_inodes+0x77c/0xef0 fs/fs-writeback.c:1926
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:1997
wb_writeback+0x464/0xba0 fs/fs-writeback.c:2107
wb_check_old_data_flush fs/fs-writeback.c:2211 [inline]
wb_do_writeback fs/fs-writeback.c:2264 [inline]
wb_workfn+0xabc/0xe20 fs/fs-writeback.c:2292
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: rcu_preempt kthread starved for 10572 jiffies! g11677 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R
stack:27752 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5380 [inline]
__schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
schedule+0xbd/0x170 kernel/sched/core.c:6773
schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 5941 Comm: syz.1.18 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__might_resched+0xdc/0x610 kernel/sched/core.c:10170
Code: 74 28 80 3d b7 7a d7 0c 00 75 1f c6 05 ae 7a d7 0c 01 48 c7 c7 20 48 aa 8a be ba 27 00 00 48 c7 c2 a0 4e aa 8a e8 14 7e 0a 00 3f 4f 0a 09 85 c0 74 46 48 c7 c7 e0 ff d2 8c be ff ff ff ff e8
RSP: 0018:ffffc900031c7780 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff92000638ef8 RCX: 62be9a3b65ce7e00
RDX: 0000000000000000 RSI: ffffffff8aaace60 RDI: ffffffff8afc6f80
RBP: ffffc900031c7898 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8aa58e00 R15: 0000000000000000
FS: 000055555c8cb500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007774d000 CR4: 00000000003506e0
Call Trace:
__might_fault+0x71/0x120 mm/memory.c:5966
__clear_user arch/x86/include/asm/uaccess_64.h:167 [inline]
copy_fpstate_to_sigframe+0x13c/0xbe0 arch/x86/kernel/fpu/signal.c:216
get_sigframe+0x5ce/0x7c0 arch/x86/kernel/signal.c:142
x64_setup_rt_frame+0x158/0xcd0 arch/x86/kernel/signal_64.c:175
setup_rt_frame arch/x86/kernel/signal.c:223 [inline]
handle_signal arch/x86/kernel/signal.c:267 [inline]
arch_do_signal_or_restart+0x3fa/0x7b0 arch/x86/kernel/signal.c:312
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4ce478f749
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff8f7baa68 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f4ce49e5fa0 RCX: 00007f4ce478f749
RDX: 0000200000000240 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f4ce4813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4ce49e5fa0 R14: 00007f4ce49e5fa0 R15: 0000000000000004