rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4423/1:b..l P1108/1:b..l
(detected by 0, t=10502 jiffies, g=7857, q=101)
task:kworker/1:2 state:R running task stack:23496 pid: 1108 ppid: 2 flags:0x00004000
Workqueue: events_power_efficient gc_worker
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:seqcount_lockdep_reader_access+0x17b/0x1c0 include/linux/seqlock.h:106
Code: f9 4d 85 e4 75 16 e8 64 af 68 f9 eb 15 e8 5d af 68 f9 e8 98 ca 92 01 4d 85 e4 74 ea e8 4e af 68 f9 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00
RSP: 0018:ffffc90004cbfa20 EFLAGS: 00000293
RAX: ffffffff880f1cc2 RBX: 0000000000000000 RCX: ffff888020eabb80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90004cbfad0 R08: dffffc0000000000 R09: fffffbfff1ff542c
R10: fffffbfff1ff542c R11: 1ffffffff1ff542b R12: 0000000000000200
R13: ffff888078bb6480 R14: 1ffff92000997f44 R15: dffffc0000000000
nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:338 [inline]
gc_worker+0x2e2/0x13a0 net/netfilter/nf_conntrack_core.c:1472
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
task:kworker/u4:6 state:R running task stack:21512 pid: 4423 ppid: 2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:419 [inline]
__test_set_page_writeback+0x7f6/0xe70 mm/page-writeback.c:2881
ext4_bio_write_page+0x293/0x1f90 fs/ext4/page-io.c:-1
mpage_submit_page+0x17a/0x210 fs/ext4/inode.c:2113
mpage_map_and_submit_buffers fs/ext4/inode.c:2361 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2500 [inline]
ext4_writepages+0x1a1f/0x2d20 fs/ext4/inode.c:2829
do_writepages+0x48d/0x6d0 mm/page-writeback.c:2386
__writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1940
__writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
wb_writeback+0x455/0xb90 fs/fs-writeback.c:2116
wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
wb_do_writeback fs/fs-writeback.c:2269 [inline]
wb_workfn+0xaaa/0xe60 fs/fs-writeback.c:2298
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: rcu_preempt kthread starved for 10563 jiffies! g7857 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 running task stack:27528 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4437 Comm: syz.3.20 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:22 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:do_softirq+0x7f/0x200 kernel/softirq.c:472
Code: f1 f1 00 f2 f2 f2 4b 89 04 37 66 43 c7 44 37 09 f3 f3 43 c6 44 37 0b f3 65 8b 05 44 fb b9 7e a9 00 ff ff 00 0f 85 fe 00 00 00 <48> c7 44 24 40 00 00 00 00 9c 8f 44 24 40 4c 8b 64 24 40 fa 41 f7
RSP: 0018:ffffc9000384f9c0 EFLAGS: 00000046
RAX: 0000000080000001 RBX: 0000000000000200 RCX: f641f42037b60b00
RDX: dffffc0000000000 RSI: ffffffff8a0a03e0 RDI: ffffffff8a59e800
RBP: ffffc9000384fa70 R08: dffffc0000000000 R09: ffffed100f0d9771
R10: ffffed100f0d9771 R11: 1ffff1100f0d9770 R12: ffffffff812bde55
R13: 1ffff1100f0d9a61 R14: dffffc0000000000 R15: 1ffff92000709f38
FS: 000055555793a500(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000022237000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__local_bh_enable_ip+0x174/0x1b0 kernel/softirq.c:401
fpregs_unlock arch/x86/include/asm/fpu/api.h:78 [inline]
copy_fpstate_to_sigframe+0x7f8/0xb90 arch/x86/kernel/fpu/signal.c:205
get_sigframe arch/x86/kernel/signal.c:295 [inline]
__setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
handle_signal arch/x86/kernel/signal.c:824 [inline]
arch_do_signal_or_restart+0x67a/0x1300 arch/x86/kernel/signal.c:869
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f549d230749
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:00007ffee1446078 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f549d486fa0 RCX: 00007f549d230749
RDX: 000020000006b000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007f549d2b4f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f549d486fa0 R14: 00007f549d486fa0 R15: 0000000000000004
sched: RT throttling activated