syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5201/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=8985, q=3767456 ncpus=2)
task:syslogd         state:R  running task     stack:23104 pid:5201  tgid:5201  ppid:1      flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7078
 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:memset+0xf/0x20 arch/x86/lib/memset_64.S:37
Code: 44 88 1f e9 be e6 24 00 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 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 e9 92 e6 24 00 0f 1f 80 00 00 00 00 90 90 90 90 90
RSP: 0018:ffffc90003d66e78 EFLAGS: 00000202
RAX: ffff88806e109e00 RBX: ffff88806e109e00 RCX: 000000000000001c
RDX: 0000000000000060 RSI: 0000000000000000 RDI: ffffc90003d66f24
RBP: dffffc0000000000 R08: ffffc90003d66f3f R09: ffffc90003d66ee0
R10: dffffc0000000000 R11: fffff520007acde8 R12: 0000000000000000
R13: ffffffff8180b700 R14: ffffc90003d66ee0 R15: 0000000000000000
 __unwind_start+0x36/0x740 arch/x86/kernel/unwind_orc.c:688
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe5/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 save_stack+0xfb/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x76/0x430 mm/page_owner.c:297
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xdf9/0x1140 mm/page_alloc.c:2657
 discard_slab mm/slub.c:2677 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:3145
 put_cpu_partial+0x17c/0x250 mm/slub.c:3220
 __slab_free+0x2ea/0x3d0 mm/slub.c:4449
 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_kmalloc+0x23/0xb0 mm/kasan/common.c:385
 kasan_kmalloc include/linux/kasan.h:257 [inline]
 __do_kmalloc_node mm/slub.c:4264 [inline]
 __kmalloc_noprof+0x1fc/0x400 mm/slub.c:4276
 kmalloc_noprof include/linux/slab.h:883 [inline]
 kzalloc_noprof include/linux/slab.h:1015 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x258/0x4f0 security/tomoyo/file.c:771
 security_file_open+0x777/0x990 security/security.c:3108
 do_dentry_open+0x369/0x1460 fs/open.c:928
 vfs_open+0x3e/0x330 fs/open.c:1071
 do_open fs/namei.c:3828 [inline]
 path_openat+0x2c84/0x3590 fs/namei.c:3987
 do_filp_open+0x27f/0x4e0 fs/namei.c:4014
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1398
 do_sys_open fs/open.c:1413 [inline]
 __do_sys_openat fs/open.c:1429 [inline]
 __se_sys_openat fs/open.c:1424 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1424
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f62c51c59a4
RSP: 002b:00007ffeea64ba40 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000565208a4c910 RCX: 00007f62c51c59a4
RDX: 0000000000000d41 RSI: 00007f62c5364443 RDI: 00000000ffffff9c
RBP: 00007f62c5364443 R08: 0000000000000001 R09: 0000000000000000
R10: 00000000000001b6 R11: 0000000000000246 R12: 0000000000000d41
R13: 00000000673f366c R14: 0000000000000003 R15: 0000565208a4ca60
 </TASK>
rcu: rcu_preempt kthread starved for 9058 jiffies! g8985 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:26264 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5369 [inline]
 __schedule+0x1850/0x4c30 kernel/sched/core.c:6756
 __schedule_loop kernel/sched/core.c:6833 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6848
 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-syzkaller-03657-g43fb83c17ba2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
RIP: 0010:preempt_count_add+0x25/0x190 kernel/sched/core.c:5843
Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 89 fb 48 c7 c0 c0 b9 3f 9a 48 c1 e8 03 49 bf 00 00 00 00 00 fc ff df 42 0f b6 04 38 <84> c0 0f 85 ed 00 00 00 83 3d 9c 60 dc 18 00 75 07 65 8b 05 9b 7e
RSP: 0018:ffffc90000156450 EFLAGS: 00000212
RAX: 0000000000000004 RBX: 0000000000000001 RCX: ffffc90000157a00
RDX: dffffc0000000000 RSI: ffffffff899afe8b RDI: 0000000000000001
RBP: ffffc90000156578 R08: 0000000000000014 R09: ffffc90000156630
R10: dffffc0000000000 R11: ffffffff8180b700 R12: dffffc0000000000
R13: ffffc90000156540 R14: ffffffff899afe8b R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055559020d918 CR3: 000000000e738000 CR4: 0000000000350ef0
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 unwind_next_frame+0xb0/0x22d0 arch/x86/kernel/unwind_orc.c:479
 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x118/0x1d0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:247 [inline]
 slab_post_alloc_hook mm/slub.c:4085 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4141
 dst_alloc+0x12b/0x190 net/core/dst.c:89
 rt_dst_alloc net/ipv4/route.c:1612 [inline]
 __mkroute_output net/ipv4/route.c:2573 [inline]
 ip_route_output_key_hash_rcu+0x13cc/0x2390 net/ipv4/route.c:2795
 ip_route_output_key_hash+0x193/0x2b0 net/ipv4/route.c:2624
 __ip_route_output_key include/net/route.h:141 [inline]
 ip_route_output_flow+0x29/0x140 net/ipv4/route.c:2852
 ip_route_output_key include/net/route.h:151 [inline]
 ip_route_me_harder+0x80d/0x1300 net/ipv4/netfilter.c:53
 synproxy_send_tcp+0x356/0x6c0 net/netfilter/nf_synproxy_core.c:431
 synproxy_send_client_synack+0x8b8/0xf30 net/netfilter/nf_synproxy_core.c:484
 nft_synproxy_eval_v4+0x3ca/0x610 net/netfilter/nft_synproxy.c:59
 nft_synproxy_do_eval+0x362/0xa60 net/netfilter/nft_synproxy.c:141
 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline]
 nft_do_chain+0x4af/0x1da0 net/netfilter/nf_tables_core.c:288
 nft_do_chain_inet+0x418/0x6b0 net/netfilter/nft_chain_filter.c:161
 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
 nf_hook_slow+0xc5/0x220 net/netfilter/core.c:626
 nf_hook include/linux/netfilter.h:269 [inline]
 NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312
 NF_HOOK+0x3a6/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5670 [inline]
 __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5783
 process_backlog+0x662/0x15b0 net/core/dev.c:6115
 __napi_poll+0xcd/0x490 net/core/dev.c:6779
 napi_poll net/core/dev.c:6848 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:6970
 handle_softirqs+0x2c7/0x980 kernel/softirq.c:554
 run_ksoftirqd+0xca/0x130 kernel/softirq.c:943
 smpboot_thread_fn+0x546/0xa30 kernel/smpboot.c:164
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 4.670 msecs