rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5203/1:b..l rcu: (detected by 0, t=10503 jiffies, g=90457, q=883761 ncpus=2) task:udevd state:R running task stack:24224 pid:5203 tgid:5203 ppid:1 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0xe55/0x5730 kernel/sched/core.c:6690 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7012 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5790 Code: b8 ff ff ff ff 65 0f c1 05 a0 d9 97 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7 RSP: 0018:ffffc90003167640 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 1ffff9200062cec9 RCX: 0000000000000001 RDX: 0000000000000001 RSI: ffffffff8b6cd3c0 RDI: ffffffff8bd1ad40 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dc5788 R10: ffffffff96e2bc47 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8e1b8380 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] page_ext_get+0x3a/0x310 mm/page_ext.c:525 __page_table_check_zero+0xbf/0x360 mm/page_table_check.c:148 page_table_check_free include/linux/page_table_check.h:41 [inline] free_pages_prepare mm/page_alloc.c:1109 [inline] free_unref_page+0x5e5/0xdc0 mm/page_alloc.c:2638 __put_partials+0x14c/0x170 mm/slub.c:3145 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x120 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:385 kasan_kmalloc include/linux/kasan.h:257 [inline] __do_kmalloc_node mm/slub.c:4264 [inline] __kmalloc_noprof+0x1e8/0x400 mm/slub.c:4276 kmalloc_noprof include/linux/slab.h:882 [inline] kzalloc_noprof include/linux/slab.h:1014 [inline] tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x19d/0x720 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x273/0x450 security/tomoyo/file.c:822 security_inode_getattr+0x116/0x290 security/security.c:2373 vfs_getattr+0x36/0xb0 fs/stat.c:204 vfs_statx_path+0x36/0x390 fs/stat.c:251 vfs_statx+0x145/0x1e0 fs/stat.c:315 vfs_fstatat+0x9f/0x160 fs/stat.c:341 __do_sys_newfstatat+0xa2/0x130 fs/stat.c:505 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe3c9d165f4 RSP: 002b:00007fffce0a24f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000557b3b0c96d8 RCX: 00007fe3c9d165f4 RDX: 00007fffce0a2508 RSI: 0000557b3b0b9897 RDI: 00000000ffffff9c RBP: 0000557b4687ea48 R08: 00062570d7d640a0 R09: 00007fe3ca1e8080 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00062570d7d640a0 R15: 0000557b3b0bddca rcu: rcu_preempt kthread starved for 3648 jiffies! g90457 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:26352 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5328 [inline] __schedule+0xe55/0x5730 kernel/sched/core.c:6690 __schedule_loop kernel/sched/core.c:6767 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6782 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 16 Comm: ksoftirqd/0 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x70 kernel/kcov.c:213 Code: 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 65 48 8b 15 74 5b 76 7e 65 8b 05 75 5b 76 7e a9 00 01 ff 00 <48> 8b 34 24 74 1d f6 c4 01 74 43 a9 00 00 0f 00 75 3c a9 00 00 f0 RSP: 0018:ffffc90000157150 EFLAGS: 00000206 RAX: 0000000080000100 RBX: ffff88822fa9f500 RCX: ffffffff89acf4aa RDX: ffff88801c2fda00 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000001 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88807e77af03 R13: 0000000000000000 R14: ffffffff89acf310 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fffeb55f8ac CR3: 000000006c6bc000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ipv4_conntrack_defrag+0x1ae/0x600 net/ipv4/netfilter/nf_defrag_ipv4.c:70 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook+0x386/0x6d0 include/linux/netfilter.h:269 __ip_local_out+0x339/0x640 net/ipv4/ip_output.c:119 ip_local_out+0x2a/0x4a0 net/ipv4/ip_output.c:128 synproxy_send_tcp.isra.0+0x439/0x630 net/netfilter/nf_synproxy_core.c:439 synproxy_send_client_synack+0x94c/0xcf0 net/netfilter/nf_synproxy_core.c:484 nft_synproxy_eval_v4 net/netfilter/nft_synproxy.c:59 [inline] nft_synproxy_do_eval+0xa49/0xd60 net/netfilter/nft_synproxy.c:141 expr_call_ops_eval net/netfilter/nf_tables_core.c:240 [inline] nft_do_chain+0x2e6/0x18f0 net/netfilter/nf_tables_core.c:288 nft_do_chain_inet+0x18b/0x350 net/netfilter/nft_chain_filter.c:161 nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline] nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626 nf_hook.constprop.0+0x42e/0x750 include/linux/netfilter.h:269 NF_HOOK include/linux/netfilter.h:312 [inline] ip_local_deliver+0x169/0x1f0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_rcv_finish net/ipv4/ip_input.c:449 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:569 __netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5666 __netif_receive_skb+0x1d/0x160 net/core/dev.c:5779 process_backlog+0x443/0x15f0 net/core/dev.c:6111 __napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6775 napi_poll net/core/dev.c:6844 [inline] net_rx_action+0xa92/0x1010 net/core/dev.c:6966 handle_softirqs+0x213/0x8f0 kernel/softirq.c:554 run_ksoftirqd kernel/softirq.c:927 [inline] run_ksoftirqd+0x3a/0x60 kernel/softirq.c:919 smpboot_thread_fn+0x661/0xa30 kernel/smpboot.c:164 kthread+0x2c1/0x3a0 kernel/kthread.c:389 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244