rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P23915/1:b..l
rcu: (detected by 0, t=10642 jiffies, g=108597, q=778 ncpus=2)
task:syz-executor state:R running task stack:26792 pid:23915 tgid:23915 ppid:16041 task_flags:0x40044c flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
preempt_schedule_common+0x7f/0xd0 kernel/sched/core.c:7463
preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:201 [inline]
_raw_spin_unlock+0x41/0x50 kernel/locking/spinlock.c:213
spin_unlock include/linux/spinlock.h:401 [inline]
zap_pte_range mm/memory.c:2095 [inline]
zap_pmd_range mm/memory.c:2151 [inline]
zap_pud_range mm/memory.c:2179 [inline]
zap_p4d_range mm/memory.c:2200 [inline]
__zap_vma_range+0x40e1/0x4f80 mm/memory.c:2240
unmap_vmas+0x390/0x550 mm/memory.c:2309
exit_mmap+0x293/0x9f0 mm/mmap.c:1315
__mmput+0x118/0x420 kernel/fork.c:1193
exit_mm+0x221/0x2d0 kernel/exit.c:618
do_exit+0x6cd/0x2360 kernel/exit.c:1000
do_group_exit+0x22d/0x2f0 kernel/exit.c:1155
get_signal+0x121b/0x12c0 kernel/signal.c:3112
arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:66 [inline]
exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
ret_from_fork+0x593/0xb70 arch/x86/kernel/process.c:167
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread starved for 661 jiffies! g108597 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27696 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 2 Comm: kthreadd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:stack_trace_consume_entry+0x112/0x280 kernel/stacktrace.c:94
Code: 4c 89 f8 48 c1 e8 03 80 3c 10 00 74 1a 4c 89 ff 48 89 f3 49 89 d4 4c 89 c5 e8 5a 4c 85 00 49 89 e8 4c 89 e2 48 89 de 49 89 37 <41> 8b 18 41 0f b6 44 15 00 84 c0 0f 85 34 01 00 00 41 3b 1e 0f 92
RSP: 0018:ffffc90000a17698 EFLAGS: 00000246
RAX: 1ffff92000142f30 RBX: ffffc90000a17820 RCX: 8000000000000100
RDX: dffffc0000000000 RSI: ffffffff8192dd39 RDI: ffffc90000a177a0
RBP: 1ffff92000142ef6 R08: ffffc90000a177b0 R09: 000000000000002c
R10: ffffc90000a17738 R11: ffffffff81b293f0 R12: 0000000000000000
R13: 1ffff92000142ef5 R14: ffffc90000a177a8 R15: ffffc90000a17980
FS: 0000000000000000(0000) GS:ffff888124dca000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff0733298c CR3: 000000007e946000 CR4: 00000000003526f0
Call Trace:
arch_stack_walk+0x10f/0x150 arch/x86/kernel/stacktrace.c:27
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6508 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6635
skb_ext_del include/linux/skbuff.h:5116 [inline]
nf_bridge_info_free net/bridge/br_netfilter_hooks.c:157 [inline]
br_nf_dev_queue_xmit+0x4f6/0x25c0 net/bridge/br_netfilter_hooks.c:856
NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:325
br_nf_post_routing+0xa51/0xee0 net/bridge/br_netfilter_hooks.c:964
nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:280 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:323
br_forward_finish+0xd3/0x130 net/bridge/br_forward.c:66
br_nf_hook_thresh net/bridge/br_netfilter_hooks.c:1165 [inline]
br_nf_forward_finish+0xa76/0xea0 net/bridge/br_netfilter_hooks.c:667
NF_HOOK+0x64e/0x6e0 include/linux/netfilter.h:325
br_nf_forward_ip+0x7e7/0xa30 net/bridge/br_netfilter_hooks.c:721
nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:280 [inline]
NF_HOOK+0x23e/0x3f0 include/linux/netfilter.h:323
__br_forward+0x397/0x540 net/bridge/br_forward.c:115
deliver_clone net/bridge/br_forward.c:131 [inline]
maybe_deliver net/bridge/br_forward.c:191 [inline]
br_flood+0x3e3/0x8d0 net/bridge/br_forward.c:245
br_handle_frame_finish+0x1119/0x1950 net/bridge/br_input.c:229
br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1
br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1
NF_HOOK include/linux/netfilter.h:325 [inline]
br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183
nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0x1329/0x1600 net/bridge/br_input.c:451
__netif_receive_skb_core+0x989/0x30c0 net/core/dev.c:6152
__netif_receive_skb_one_core net/core/dev.c:6263 [inline]
__netif_receive_skb net/core/dev.c:6378 [inline]
process_backlog+0x727/0x18b0 net/core/dev.c:6729
__napi_poll+0xaa/0x330 net/core/dev.c:7798
napi_poll net/core/dev.c:7861 [inline]
net_rx_action+0x61d/0xf50 net/core/dev.c:8018
handle_softirqs+0x226/0x860 kernel/softirq.c:645
__do_softirq kernel/softirq.c:679 [inline]
invoke_softirq kernel/softirq.c:519 [inline]
__irq_exit_rcu+0xcb/0x220 kernel/softirq.c:758
irq_exit_rcu+0x9/0x30 kernel/softirq.c:775
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5947
Code: ff ff ff e8 40 3c 43 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 62 27 f2 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 7f 40 46 0a cc 48 8d 3d 87 61 da
RSP: 0018:ffffc900000772a0 EFLAGS: 00000296
RAX: 795f310a25f27e00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 0000000006ca7f8c RSI: ffffffff8e69f169 RDI: ffffffff8c6dac80
RBP: ffff88801dae3e80 R08: ffffffff8177f1df R09: 0000000000000000
R10: ffffc900000773d8 R11: ffffffff81b293f0 R12: ffffffff8ed5c920
R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
rcu_read_lock include/linux/rcupdate.h:849 [inline]
class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:183
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:338
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
__free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962
__slab_free+0x274/0x2c0 mm/slub.c:5823
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4683 [inline]
slab_alloc_node mm/slub.c:4996 [inline]
kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010
prepare_creds+0x30/0x820 kernel/cred.c:185
copy_creds+0x109/0x9f0 kernel/cred.c:286
copy_process+0xcf9/0x4400 kernel/fork.c:2174
kernel_clone+0x2d7/0x940 kernel/fork.c:2769
kernel_thread+0x13f/0x1b0 kernel/fork.c:2830
create_kthread kernel/kthread.c:459 [inline]
kthreadd+0x4ec/0x6e0 kernel/kthread.c:817
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245