rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11608/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=476357, q=1726 ncpus=2)
task:syz.4.11450 state:R running task stack:24872 pid:11608 tgid:11600 ppid:2876 task_flags:0x40044c flags:0x08080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:uncharge_batch+0xa5/0x3a0 mm/memcontrol.c:5131
Code: 8b e8 9f 47 68 ff 48 b8 00 00 00 00 00 fc ff df 48 89 d9 48 c1 e9 03 48 89 4c 24 08 80 3c 01 00 74 08 48 89 df e8 7b 51 f7 ff <4c> 8b 3b 48 c7 c0 c0 0d 31 90 48 c1 e8 03 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc9000535edf8 EFLAGS: 00000246
RAX: dffffc0000000000 RBX: ffffc9000535ee80 RCX: 1ffff92000a6bdd0
RDX: 00000000cdac3f13 RSI: ffffffff8c28b740 RDI: ffffffff8c28b700
RBP: ffffc9000535ef30 R08: ffffffff8239a76d R09: ffffffff8e95cce0
R10: dffffc0000000000 R11: fffff94000360389 R12: 000000000000001f
R13: dffffc0000000000 R14: ffffffff8239a76d R15: ffffc9000535f1c0
__mem_cgroup_uncharge_folios+0x14f/0x1d0 mm/memcontrol.c:5216
mem_cgroup_uncharge_folios include/linux/memcontrol.h:672 [inline]
folios_put_refs+0x9f7/0xb40 mm/swap.c:1007
free_pages_and_swap_cache+0x2b9/0x490 mm/swap_state.c:401
__tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline]
tlb_batch_pages_flush mm/mmu_gather.c:151 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:417 [inline]
tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:424
zap_pte_range mm/memory.c:1973 [inline]
zap_pmd_range mm/memory.c:2020 [inline]
zap_pud_range mm/memory.c:2048 [inline]
zap_p4d_range mm/memory.c:2069 [inline]
__zap_vma_range+0x3de2/0x4b70 mm/memory.c:2109
unmap_vmas+0x3ac/0x570 mm/memory.c:2178
exit_mmap+0x280/0x9e0 mm/mmap.c:1300
__mmput+0x118/0x430 kernel/fork.c:1178
exit_mm+0x1f6/0x2d0 kernel/exit.c:582
do_exit+0x6a2/0x22c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
get_signal+0x1284/0x1330 kernel/signal.c:3037
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
__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:318 [inline]
__do_fast_syscall_32+0x446/0x6e0 arch/x86/entry/syscall_32.c:310
do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:332
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fd401c
RSP: 002b:00000000f54545bc EFLAGS: 00000206 ORIG_RAX: 00000000000000f0
RAX: fffffffffffffe00 RBX: 00000000f74950b8 RCX: 0000000000000080
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000f74950bc
RBP: 0000000000000081 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 818 jiffies! g476357 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x389/0x470 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:
CPU: 1 UID: 0 PID: 3982 Comm: kworker/u8:13 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: krds_cp_wq#8/3 rds_connect_worker
RIP: 0010:rcu_preempt_read_exit kernel/rcu/tree_plugin.h:396 [inline]
RIP: 0010:__rcu_read_unlock+0x32/0xe0 kernel/rcu/tree_plugin.h:435
Code: 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff df 65 48 8b 3d 59 0c 8e 11 48 8d 9f c4 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c <84> c0 75 4f ff 0b 75 1d 4c 8d b7 c8 04 00 00 4c 89 f0 48 c1 e8 03
RSP: 0018:ffffc90000a07e88 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: ffff88807c756104 RCX: 0000000080000101
RDX: 0000000000000006 RSI: ffffffff8e220b4c RDI: ffff88807c755c40
RBP: dffffc0000000000 R08: ffffc90000a087f0 R09: 0000000000000000
R10: ffffc90000a07fd8 R11: fffff52000140ffd R12: 1ffff1100f8eac20
R13: ffffc90000a01000 R14: ffffc90000a07f88 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125387000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000005843f470 CR3: 000000004cbe4000 CR4: 00000000003526f0
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
class_rcu_destructor include/linux/rcupdate.h:1181 [inline]
unwind_next_frame+0x1bbf/0x2550 arch/x86/kernel/unwind_orc.c:709
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
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+0x46/0x50 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:2689 [inline]
slab_free mm/slub.c:6251 [inline]
kmem_cache_free+0x182/0x650 mm/slub.c:6378
nft_synproxy_eval_v6+0x352/0x4e0 net/netfilter/nft_synproxy.c:92
nft_synproxy_do_eval+0x3ce/0x580 net/netfilter/nft_synproxy.c:146
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x48d/0x1ae0 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x360/0x4b0 net/netfilter/nft_chain_filter.c:162
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:316
ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:545
NF_HOOK+0x336/0x3c0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6202 [inline]
__netif_receive_skb net/core/dev.c:6315 [inline]
process_backlog+0x7dd/0x1950 net/core/dev.c:6666
__napi_poll+0xae/0x340 net/core/dev.c:7733
napi_poll net/core/dev.c:7796 [inline]
net_rx_action+0x627/0xf70 net/core/dev.c:7953
handle_softirqs+0x22a/0x840 kernel/softirq.c:622
do_softirq+0x76/0xd0 kernel/softirq.c:523
__local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
__inet6_bind+0x399/0xf60 net/ipv6/af_inet6.c:419
kernel_bind+0x13e/0x1c0 net/socket.c:3660
rds_tcp_conn_path_connect+0x53e/0x930 net/rds/tcp_connect.c:175
rds_connect_worker+0x1d8/0x290 net/rds/threads.c:176
process_one_work kernel/workqueue.c:3314 [inline]
process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3397
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3478
kthread+0x389/0x470 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