syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P8643/1:b..l
rcu: 	(detected by 0, t=10503 jiffies, g=18741, q=1102125 ncpus=2)
task:syz-executor    state:R  running task     stack:23624 pid:8643  tgid:8643  ppid:5828   task_flags:0x400000 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b88/0x5240 kernel/sched/core.c:6767
 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x18a8/0x23b0 arch/x86/kernel/unwind_orc.c:-1
Code: f8 48 c1 e8 03 0f b6 04 28 84 c0 0f 85 5c 0a 00 00 48 0f bf 03 48 8b 74 24 08 48 01 c6 49 8d 54 24 40 4c 89 e7 e8 38 0e 00 00 <84> c0 0f 84 52 01 00 00 49 bd 00 00 00 00 00 fc ff df 48 8b 44 24
RSP: 0018:ffffc9000b52eea8 EFLAGS: 00000282
RAX: 1ffff920016a5d01 RBX: ffffffff90f7b77e RCX: 0000000000000000
RDX: dffffc0000000000 RSI: ffffc9000b528000 RDI: ffffc9000b52f3a8
RBP: dffffc0000000000 R08: ffffc9000b52f3a8 R09: 0000000000000000
R10: ffffc9000b52efd0 R11: fffff520016a5dfc R12: ffffc9000b52ef80
R13: ffffc9000b530000 R14: ffffffff90f7b780 R15: ffffffff90f7b77f
 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfc/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x1e0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0xde8/0x10a0 mm/page_alloc.c:2725
 __slab_free+0x2c6/0x390 mm/slub.c:4567
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4161 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 kmem_cache_alloc_noprof+0x1e1/0x390 mm/slub.c:4217
 ptlock_alloc+0x20/0x70 mm/memory.c:7354
 ptlock_init include/linux/mm.h:3074 [inline]
 pagetable_pte_ctor include/linux/mm.h:3122 [inline]
 __pte_alloc_one_noprof include/asm-generic/pgalloc.h:73 [inline]
 pte_alloc_one+0x6d/0x160 arch/x86/mm/pgtable.c:17
 __pte_alloc+0x7b/0x240 mm/memory.c:430
 __get_locked_pte mm/memory.c:2075 [inline]
 get_locked_pte include/linux/mm.h:2843 [inline]
 insert_page+0x2e7/0x310 mm/memory.c:2179
 kcov_mmap+0xc6/0x130 kernel/kcov.c:506
 call_mmap include/linux/fs.h:2243 [inline]
 mmap_file mm/internal.h:167 [inline]
 __mmap_new_file_vma mm/vma.c:2353 [inline]
 __mmap_new_vma mm/vma.c:2417 [inline]
 __mmap_region mm/vma.c:2519 [inline]
 mmap_region+0x241d/0x2ea0 mm/vma.c:2597
 do_mmap+0xd42/0x1420 mm/mmap.c:561
 vm_mmap_pgoff+0x2a2/0x530 mm/util.c:579
 ksys_mmap_pgoff+0x4ee/0x720 mm/mmap.c:607
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb6c038e1a3
RSP: 002b:00007ffcb6969c58 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007fb6c05b6118 RCX: 00007fb6c038e1a3
RDX: 0000000000000003 RSI: 0000000000400000 RDI: 00007fb6bf5fd000
RBP: 00007fb6c05b6118 R08: 00000000000000d9 R09: 0000000000000000
R10: 0000000000000011 R11: 0000000000000246 R12: 0000000000000008
R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 8498 jiffies! g18741 f0x2 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:26376 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b88/0x5240 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248
 kthread+0x7b7/0x940 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc3-syzkaller-00001-g9d7a0577c9db #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:100 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:233 [inline]
RIP: 0010:unwind_next_frame+0x114e/0x23b0 arch/x86/kernel/unwind_orc.c:494
Code: e3 90 49 c7 c5 38 d6 6d 90 4c 29 e9 48 21 c1 4c 8d 34 11 49 81 c6 38 d6 6d 90 48 c7 c5 38 d6 6d 90 4c 89 f0 48 29 e8 48 89 c1 <48> c1 f9 02 48 c1 e8 3f 48 01 c8 48 83 e0 fe 48 8d 1c 45 00 00 00
RSP: 0018:ffffc90000006b88 EFLAGS: 00000206
RAX: 000000000001d4ac RBX: ffffffff90e12ef0 RCX: 000000000001d4ac
RDX: fffffffffffffffc RSI: ffffffff8ca1b660 RDI: ffffffff8ca1b620
RBP: ffffffff90df5a40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff91c1b739
R13: ffffffff90df5a3c R14: ffffffff90e12eec R15: ffffffff816d9bc8
FS:  0000000000000000(0000) GS:ffff888124f9a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000158030 CR3: 00000000341a0000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2398 [inline]
 slab_free mm/slub.c:4656 [inline]
 kmem_cache_free+0x197/0x410 mm/slub.c:4758
 nft_synproxy_eval_v4+0x3d4/0x610 net/netfilter/nft_synproxy.c:60
 nft_synproxy_do_eval+0x36a/0xa90 net/netfilter/nft_synproxy.c:141
 expr_call_ops_eval net/netfilter/nf_tables_core.c:237 [inline]
 nft_do_chain+0x4b2/0x1db0 net/netfilter/nf_tables_core.c:285
 nft_do_chain_inet+0x41f/0x6b0 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc8/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x29b/0x450 include/linux/netfilter.h:312
 NF_HOOK+0x3a0/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5887 [inline]
 __netif_receive_skb+0x2c9/0x670 net/core/dev.c:6000
 process_backlog+0x664/0x15c0 net/core/dev.c:6352
 __napi_poll+0xcb/0x480 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0x89d/0x1240 net/core/dev.c:7510
 handle_softirqs+0x2d6/0x9b0 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xfb/0x220 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1049
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: cc cc cc cc cc cc cc 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 53 7e 18 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8ea07d60 EFLAGS: 000002c6
RAX: b1acb4e7c0f72500 RBX: ffffffff8197272e RCX: ffffffff8c2fb89c
RDX: 0000000000000001 RSI: ffffffff8e6497f7 RDI: ffffffff8ca1b680
RBP: ffffffff8ea07eb8 R08: ffff8880b8632b5b R09: 1ffff110170c656b
R10: dffffc0000000000 R11: ffffed10170c656c R12: 1ffffffff1d40fc6
R13: 1ffffffff1d52cb0 R14: 0000000000000000 R15: dffffc0000000000
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x22e/0x5d0 kernel/sched/idle.c:325
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423
 rest_init+0x2dc/0x300 init/main.c:743
 start_kernel+0x484/0x510 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x147
 </TASK>