rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P17814/1:b..l P1093/1:b..l
rcu: (detected by 0, t=10503 jiffies, g=111441, q=865915 ncpus=2)
task:kworker/u8:5 state:R running task stack:21864 pid:1093 tgid:1093 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: iou_exit io_ring_exit_work
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:memset_orig+0x25/0xb0 arch/x86/lib/memset_64.S:64
Code: 90 90 90 90 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 01 01 01 48 0f af c1 41 89 f9 41 83 e1 07 75 74 48 89 d1 48 c1 e9 06 <74> 39 66 0f 1f 84 00 00 00 00 00 48 ff c9 48 89 07 48 89 47 08 48
RSP: 0018:ffffc90003c3f390 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffc90003c3f4a0 RCX: 0000000000000000
RDX: 0000000000000010 RSI: 0000000000000000 RDI: ffffc90003c3f4b8
RBP: dffffc0000000000 R08: ffffc90003c3f4c7 R09: 0000000000000000
R10: ffffc90003c3f4b8 R11: fffff52000787e99 R12: ffffc90003c3fd80
R13: ffffc90003c3f4b8 R14: ffffc90003c3f468 R15: ffffc90003c3f4b0
unwind_next_frame+0xc98/0x2390 arch/x86/kernel/unwind_orc.c:592
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
slab_free_hook mm/slub.c:2504 [inline]
slab_free mm/slub.c:6642 [inline]
kmem_cache_free+0x4a2/0x690 mm/slub.c:6752
__io_req_caches_free+0x1c1/0x270 io_uring/io_uring.c:2824
io_req_caches_free+0x21/0x60 io_uring/io_uring.c:2836
io_ring_exit_work+0x415/0x930 io_uring/io_uring.c:3034
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:syz.1.3371 state:R running task stack:24616 pid:17814 tgid:17814 ppid:16878 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 5b fd d0 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0000:ffffc9000bddf218 EFLAGS: 00000206
RAX: 8040a5680244c900 RBX: 0000000000000000 RCX: 8040a5680244c900
RDX: 0000000000000000 RSI: ffffffff8d8f50ca RDI: ffffffff8bbf08e0
RBP: ffffffff81738c45 R08: 0000000000000000 R09: ffffffff81738c45
R10: ffffc9000bddf3d8 R11: ffffffff81ac2e10 R12: 0000000000000002
R13: ffffffff8df3d6e0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:311
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2901
discard_slab mm/slub.c:3330 [inline]
__put_partials+0x146/0x170 mm/slub.c:3876
put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3951
__slab_free+0x2b9/0x390 mm/slub.c:5929
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4978 [inline]
slab_alloc_node mm/slub.c:5288 [inline]
kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5295
new_handle fs/jbd2/transaction.c:457 [inline]
jbd2__journal_start+0x146/0x5b0 fs/jbd2/transaction.c:484
__ext4_journal_start_sb+0x227/0x5c0 fs/ext4/ext4_jbd2.c:115
__ext4_journal_start fs/ext4/ext4_jbd2.h:242 [inline]
ext4_dirty_inode+0x93/0x110 fs/ext4/inode.c:6514
__mark_inode_dirty+0x2ec/0xe10 fs/fs-writeback.c:2566
generic_update_time fs/inode.c:2117 [inline]
inode_update_time fs/inode.c:2130 [inline]
__file_update_time fs/inode.c:2357 [inline]
file_update_time+0x40c/0x490 fs/inode.c:2387
ext4_page_mkwrite+0x20e/0x1190 fs/ext4/inode.c:6683
do_page_mkwrite+0x14d/0x310 mm/memory.c:3489
do_shared_fault mm/memory.c:5792 [inline]
do_fault mm/memory.c:5854 [inline]
do_pte_missing mm/memory.c:4362 [inline]
handle_pte_fault mm/memory.c:6195 [inline]
__handle_mm_fault+0x1916/0x5400 mm/memory.c:6336
handle_mm_fault+0x40a/0x8e0 mm/memory.c:6505
do_user_addr_fault+0xa7c/0x1380 arch/x86/mm/fault.c:1336
handle_page_fault arch/x86/mm/fault.c:1476 [inline]
exc_page_fault+0x82/0x100 arch/x86/mm/fault.c:1532
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f529006f8c2
RSP: 002b:00007f529050fad0 EFLAGS: 00010202
RAX: 000000000001d008 RBX: 00007f5290f15720 RCX: 0000000000000000
RDX: 0000001b31007000 RSI: 0000000000000008 RDI: 00007f5290f15720
RBP: 00000000000001f6 R08: 00007f528f7fd060 R09: 00007f52903d2000
R10: 00007f528f7fd008 R11: 0000000000000004 R12: ffffffff81fc5630
R13: 00007f52903e6128 R14: 000000000000019c R15: fffffffffffe3000
rcu: rcu_preempt kthread starved for 3226 jiffies! g111441 f0x2 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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: 34 Comm: kcompactd0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:kfree_skbmem+0x62/0x1c0 net/core/skbuff.c:1110
Code: 41 83 e6 03 4c 89 f7 48 c7 c6 20 b6 2b 8f e8 d5 29 a0 f8 41 83 fe 01 74 34 45 85 f6 75 72 e8 45 24 a0 f8 48 c7 c0 d0 6d c6 8d <48> c1 e8 03 42 80 3c 38 00 74 0c 48 c7 c7 d0 6d c6 8d e8 e7 e5 05
RSP: 0000:ffffc90000a081f8 EFLAGS: 00000246
RAX: ffffffff8dc66dd0 RBX: ffff88804e486dc0 RCX: ffff888020e83c80
RDX: 0000000000000100 RSI: ffffffff8f2bb620 RDI: 0000000000000000
RBP: ffffc90000a082f0 R08: ffff888020e83c80 R09: 0000000000000002
R10: 0000000000000001 R11: 0000000000000100 R12: 1ffff9200014106c
R13: 0000000000000000 R14: 0000000000000000 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff88812623b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f10b5213de2 CR3: 000000000dd38000 CR4: 00000000003526f0
Call Trace:
nft_synproxy_eval_v4+0x376/0x560 net/netfilter/nft_synproxy.c:60
nft_synproxy_do_eval+0x345/0x570 net/netfilter/nft_synproxy.c:141
expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
nft_do_chain+0x40c/0x1920 net/netfilter/nf_tables_core.c:285
nft_do_chain_inet+0x25d/0x340 net/netfilter/nft_chain_filter.c:161
nf_hook_entry_hookfn include/linux/netfilter.h:158 [inline]
nf_hook_slow+0xc5/0x220 net/netfilter/core.c:623
nf_hook include/linux/netfilter.h:273 [inline]
NF_HOOK+0x206/0x3a0 include/linux/netfilter.h:316
NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
__netif_receive_skb_one_core net/core/dev.c:6079 [inline]
__netif_receive_skb+0x143/0x380 net/core/dev.c:6192
process_backlog+0x60e/0x14f0 net/core/dev.c:6544
__napi_poll+0xc7/0x360 net/core/dev.c:7594
napi_poll net/core/dev.c:7657 [inline]
net_rx_action+0x5f7/0xdf0 net/core/dev.c:7784
handle_softirqs+0x286/0x870 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0xca/0x1f0 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+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 e6 73 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 91 6f 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 75 6f 0b 00 eb e4 44
RSP: 0000:ffffc90000aa6f60 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff11017108441 RCX: ffff888020e83c80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000aa70e0 R08: ffffffff8f7cee77 R09: 1ffffffff1ef9dce
R10: dffffc0000000000 R11: fffffbfff1ef9dcf R12: ffff8880b8842208
R13: dffffc0000000000 R14: ffff8880b893b240 R15: 0000000000000000
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1381 [inline]
arch_tlbbatch_flush+0x324/0x570 arch/x86/mm/tlb.c:1745
try_to_unmap_flush+0x51/0xd0 mm/rmap.c:649
migrate_pages_batch+0x18f8/0x35e0 mm/migrate.c:1960
migrate_pages_sync mm/migrate.c:1999 [inline]
migrate_pages+0x1bcc/0x2930 mm/migrate.c:2108
compact_zone+0x23e1/0x4ab0 mm/compaction.c:2647
kcompactd_do_work mm/compaction.c:3098 [inline]
kcompactd+0x97d/0x1290 mm/compaction.c:3192
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245