rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8096/1:b..l P8102/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=21297, q=679 ncpus=2)
task:syz.1.461 state:R running task stack:26536 pid:8102 tgid:8102 ppid:5802 task_flags:0x40044c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:7188
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:753
rcu_read_lock include/linux/rcupdate.h:848 [inline]
class_rcu_constructor include/linux/rcupdate.h:1190 [inline]
unwind_next_frame+0x6fa/0x1ea0 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
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2685 [inline]
slab_free mm/slub.c:6165 [inline]
kmem_cache_free+0x124/0x6a0 mm/slub.c:6295
anon_vma_chain_free mm/rmap.c:147 [inline]
unlink_anon_vmas+0x228/0x8e0 mm/rmap.c:514
free_pgtables+0x2e7/0xd80 mm/memory.c:427
exit_mmap+0x44c/0xa30 mm/mmap.c:1314
__mmput+0x12a/0x410 kernel/fork.c:1175
mmput+0x67/0x80 kernel/fork.c:1198
exit_mm kernel/exit.c:581 [inline]
do_exit+0x819/0x2b60 kernel/exit.c:964
do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9c1b39c819
RSP: 002b:00007ffe5c37a308 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000000 RBX: 0000000000047caf RCX: 00007f9c1b39c819
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f9c1b61609c
RBP: 0000000000000032 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffe5c37a410 R11: 0000000000000246 R12: 00007ffe5c37a430
R13: 00007f9c1b61609c R14: 0000000000047ce1 R15: 00007ffe5c37a410
task:syz.6.459 state:R running task stack:26744 pid:8096 tgid:8094 ppid:7223 task_flags:0x40044c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872
Code: 05 7b ae 29 12 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 46 e0 f4 0e 0f 82 c2 02 00 00 8b 35 2e 14 f5 0e 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 1d ae 29 12 0f 85 02 03 00 00 48 83 c4
RSP: 0018:ffffc9000604ed08 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8de55be0 RDI: ffffffff8c1b23a0
RBP: ffffffff8e7e77a0 R08: 000000009ce532ca R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:847 [inline]
class_rcu_constructor include/linux/rcupdate.h:1190 [inline]
unwind_next_frame+0xd1/0x1ea0 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
save_stack+0x162/0x1e0 mm/page_owner.c:165
__reset_page_owner+0x84/0x190 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1433 [inline]
free_unref_folios+0xaea/0x1790 mm/page_alloc.c:3040
folios_put_refs+0x53c/0x840 mm/swap.c:1002
free_pages_and_swap_cache+0x242/0x480 mm/swap_state.c:423
__tlb_batch_free_encoded_pages+0xe9/0x280 mm/mmu_gather.c:138
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:398 [inline]
tlb_flush_mmu+0xe9/0x590 mm/mmu_gather.c:405
zap_pte_range mm/memory.c:1968 [inline]
zap_pmd_range mm/memory.c:2021 [inline]
zap_pud_range mm/memory.c:2049 [inline]
zap_p4d_range mm/memory.c:2070 [inline]
unmap_page_range+0x2333/0x4840 mm/memory.c:2091
unmap_single_vma+0x153/0x240 mm/memory.c:2133
unmap_vmas+0x295/0x590 mm/memory.c:2171
exit_mmap+0x1ef/0xa30 mm/mmap.c:1302
__mmput+0x12a/0x410 kernel/fork.c:1175
mmput+0x67/0x80 kernel/fork.c:1198
exit_mm kernel/exit.c:581 [inline]
do_exit+0x819/0x2b60 kernel/exit.c:964
do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
do_syscall_64+0x67c/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f40e1d9c819
RSP: 002b:00007f40e2ba7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: 000000000000000b RBX: 00007f40e2015fa0 RCX: 00007f40e1d9c819
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000004
RBP: 00007f40e1e32c91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f40e2016038 R14: 00007f40e2015fa0 R15: 00007fff34e5a5b8
rcu: rcu_preempt kthread starved for 9444 jiffies! g21297 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:27976 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0xfee/0x6120 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7008
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:write_comp_data+0x7/0x90 kernel/kcov.c:240
Code: 98 16 00 00 e9 4a fa 8b 09 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 79 be 05 12 <49> 89 f8 49 89 f1 49 89 d2 65 48 8b 3d 50 be 05 12 a9 00 01 ff 00
RSP: 0018:ffffc90000a07dd8 EFLAGS: 00000246
RAX: 0000000080000301 RBX: 000000000000dd86 RCX: ffffffff89637c11
RDX: 000000000000dd86 RSI: 0000000000005865 RDI: 0000000000000003
RBP: ffff888199e55140 R08: 0000000000000003 R09: 000000000000a888
R10: 000000000000dd86 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000dd86
FS: 0000000000000000(0000) GS:ffff888124435000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563eba65a008 CR3: 000000005870d000 CR4: 00000000003526f0
Call Trace:
skb_network_protocol+0x61/0x3d0 net/core/dev.c:3668
harmonize_features net/core/dev.c:3744 [inline]
netif_skb_features+0x960/0x13f0 net/core/dev.c:3873
validate_xmit_skb+0x8c/0x1590 net/core/dev.c:4027
__dev_queue_xmit+0x1de8/0x4800 net/core/dev.c:4844
dev_queue_xmit include/linux/netdevice.h:3385 [inline]
neigh_hh_output include/net/neighbour.h:540 [inline]
neigh_output include/net/neighbour.h:554 [inline]
ip6_finish_output2+0xfd4/0x1ce0 net/ipv6/ip6_output.c:136
__ip6_finish_output+0x357/0xdf0 net/ipv6/ip6_output.c:208
ip6_finish_output net/ipv6/ip6_output.c:219 [inline]
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x2aa/0xa60 net/ipv6/ip6_output.c:246
dst_output include/net/dst.h:470 [inline]
ip6_local_out+0xcb/0x1f0 net/ipv6/output_core.c:152
synproxy_send_tcp_ipv6+0x5f3/0x700 net/netfilter/nf_synproxy_core.c:852
synproxy_send_client_synack_ipv6+0x601/0x7a0 net/netfilter/nf_synproxy_core.c:898
nft_synproxy_eval_v6 net/netfilter/nft_synproxy.c:91 [inline]
nft_synproxy_do_eval+0x941/0xd50 net/netfilter/nft_synproxy.c:146
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x2e8/0x1930 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0xee/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbf/0x220 net/netfilter/core.c:623
nf_hook.constprop.0+0x2a6/0x750 include/linux/netfilter.h:273
NF_HOOK include/linux/netfilter.h:316 [inline]
ip6_input+0xe0/0x2f0 net/ipv6/ip6_input.c:500
dst_input include/net/dst.h:480 [inline]
ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
ipv6_rcv+0x263/0x3d0 net/ipv6/ip6_input.c:311
__netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6181
__netif_receive_skb+0x1f/0x120 net/core/dev.c:6294
process_backlog+0x37a/0x1580 net/core/dev.c:6645
__napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7709
napi_poll net/core/dev.c:7772 [inline]
net_rx_action+0xa40/0xf20 net/core/dev.c:7929
handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xef/0x150 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63
Code: 28 81 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 c1 19 00 fb f4 fc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df0 EFLAGS: 00000242
RAX: 0000000002624d83 RBX: ffff88801e69a4c0 RCX: ffffffff8b91cc75
RDX: 0000000000000000 RSI: ffffffff8de7bd89 RDI: ffffffff8c1b23a0
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed10170a679d
R10: ffff8880b8533ceb R11: 0000000000000000 R12: 0000000000000001
R13: ffffed1003cd3498 R14: 0000000000000001 R15: ffffffff90d9e210
arch_safe_halt arch/x86/include/asm/paravirt.h:73 [inline]
default_idle+0x9/0x10 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:199 [inline]
do_idle+0x464/0x590 kernel/sched/idle.c:352
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:451
start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312
common_startup_64+0x13e/0x148