rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5932/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=9721, q=1614 ncpus=2)
task:syz.3.4 state:R running task stack:24136 pid:5932 tgid:5923 ppid:5837 task_flags:0x40044c flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7113
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1884 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0xf71/0x41b0 mm/memory.c:2017
unmap_single_vma.constprop.0+0x153/0x240 mm/memory.c:2060
unmap_vmas+0x218/0x470 mm/memory.c:2104
exit_mmap+0x1b2/0xb90 mm/mmap.c:1280
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:582 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:954
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x85/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x426/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff01678f6c9
RSP: 002b:00007ff01757e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: fffffffffffffffc RBX: 00007ff0169e6270 RCX: 00007ff01678f6c9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004
RBP: 00007ff016811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff0169e6308 R14: 00007ff0169e6270 R15: 00007fffb5027578
rcu: rcu_preempt kthread starved for 9700 jiffies! g9721 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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:28440 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 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:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:in_irqentry_text kernel/stacktrace.c:380 [inline]
RIP: 0010:filter_irq_stacks+0x48/0x90 kernel/stacktrace.c:397
Code: ea 03 80 3c 1a 00 75 4a 48 8b 17 48 81 fa 30 02 00 81 72 16 48 81 fa 70 16 00 81 73 0d 83 c0 01 48 83 c4 10 5b c3 cc cc cc cc <48> 81 fa 40 4b 60 8b 72 09 48 81 fa 5b 4b 60 8b 72 e1 83 c0 01 48
RSP: 0018:ffffc90000006be8 EFLAGS: 00000206
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000001
RDX: ffffffff8223cf84 RSI: 000000000000002d RDI: ffffc90000006c68
RBP: 0000000000000000 R08: ffffffff91142440 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000005d7c R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: ffffc90000006c60
FS: 0000000000000000(0000) GS:ffff888124a0d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31306ff8 CR3: 0000000072dae000 CR4: 00000000003526f0
Call Trace:
stack_depot_save_flags+0x29/0x9c0 lib/stackdepot.c:659
kasan_save_stack+0x42/0x60 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
__kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2539 [inline]
slab_free mm/slub.c:6630 [inline]
kmem_cache_free+0x2d4/0x6c0 mm/slub.c:6740
__skb_ext_put+0x102/0x2c0 net/core/skbuff.c:7160
skb_ext_put include/linux/skbuff.h:4947 [inline]
skb_ext_put include/linux/skbuff.h:4944 [inline]
skb_release_head_state+0x1c2/0x290 net/core/skbuff.c:1144
skb_release_all net/core/skbuff.c:1150 [inline]
__kfree_skb net/core/skbuff.c:1166 [inline]
sk_skb_reason_drop+0xeb/0x1a0 net/core/skbuff.c:1204
kfree_skb_reason include/linux/skbuff.h:1322 [inline]
kfree_skb include/linux/skbuff.h:1331 [inline]
ip6_mc_input+0x82c/0xf60 net/ipv6/ip6_input.c:593
dst_input include/net/dst.h:474 [inline]
dst_input include/net/dst.h:472 [inline]
ip6_rcv_finish+0x3df/0x580 net/ipv6/ip6_input.c:79
ip_sabotage_in+0x21e/0x290 net/bridge/br_netfilter_hooks.c:990
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623
nf_hook.constprop.0+0x424/0x750 include/linux/netfilter.h:273
NF_HOOK include/linux/netfilter.h:316 [inline]
ipv6_rcv+0xa4/0x650 net/ipv6/ip6_input.c:311
__netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:6079
__netif_receive_skb+0x1d/0x160 net/core/dev.c:6192
netif_receive_skb_internal net/core/dev.c:6278 [inline]
netif_receive_skb+0x137/0x7b0 net/core/dev.c:6337
NF_HOOK include/linux/netfilter.h:318 [inline]
NF_HOOK include/linux/netfilter.h:312 [inline]
br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
br_handle_frame_finish+0x10e8/0x1f00 net/bridge/br_input.c:235
br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1167
br_nf_pre_routing_finish_ipv6+0x76a/0xfc0 net/bridge/br_netfilter_ipv6.c:154
NF_HOOK include/linux/netfilter.h:318 [inline]
br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184
br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:291 [inline]
br_handle_frame+0xb28/0x14e0 net/bridge/br_input.c:442
__netif_receive_skb_core.constprop.0+0xa25/0x4bd0 net/core/dev.c:5966
__netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6077
__netif_receive_skb+0x1d/0x160 net/core/dev.c:6192
process_backlog+0x439/0x15e0 net/core/dev.c:6544
__napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7594
napi_poll net/core/dev.c:7657 [inline]
net_rx_action+0x97f/0xef0 net/core/dev.c:7784
handle_softirqs+0x219/0x8e0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x109/0x170 kernel/softirq.c:723
irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1052
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:82
Code: a7 6f 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 a3 c4 2c 00 fb f4 3c 0a 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c6
RAX: 0000000000c7528d RBX: 0000000000000000 RCX: ffffffff8b5d62a9
RDX: 0000000000000000 RSI: ffffffff8da2840b RDI: ffffffff8bf075c0
RBP: fffffbfff1c12f40 R08: 0000000000000001 R09: ffffed1017086655
R10: ffff8880b84332ab R11: 0000000000000001 R12: 0000000000000000
R13: ffffffff8e097a00 R14: ffffffff908241d0 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:767
default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x38d/0x500 kernel/sched/idle.c:330
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:428
rest_init+0x16b/0x2b0 init/main.c:757
start_kernel+0x3f6/0x4e0 init/main.c:1111
x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
common_startup_64+0x13e/0x148