rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4687/1:b..l rcu: (detected by 0, t=10503 jiffies, g=43409, q=1837651 ncpus=2) task:udevd state:R running task stack:21664 pid:4687 tgid:4687 ppid:1 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6997 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:rcu_lock_acquire include/linux/rcupdate.h:337 [inline] RIP: 0010:rcu_read_lock include/linux/rcupdate.h:849 [inline] RIP: 0010:page_ext_get+0x3d/0x2a0 mm/page_ext.c:525 Code: ff e8 27 4c 70 ff 4c 8d 35 00 00 00 00 48 c7 c7 e0 7d 93 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 56 e8 93 e9 64 ff <48> 83 c4 08 e8 fa f2 b9 09 89 c5 31 ff 89 c6 e8 6f 85 89 ff 85 ed RSP: 0018:ffffc9000348f5a8 EFLAGS: 00000246 RAX: 08ad7054f610e600 RBX: ffffea00017a07c0 RCX: 08ad7054f610e600 RDX: dffffc0000000000 RSI: ffffffff8c0adc40 RDI: ffffffff8c60f860 RBP: dffffc0000000000 R08: ffffffff942c5807 R09: 1ffffffff2858b00 R10: dffffc0000000000 R11: fffffbfff2858b01 R12: 0000000000000000 R13: ffffea00017a07c8 R14: ffffffff820b5a50 R15: 1ffffd40002f40f8 __page_table_check_zero+0xb1/0x350 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+0xd0f/0xf20 mm/page_alloc.c:2638 discard_slab mm/slub.c:2678 [inline] __put_partials+0xeb/0x130 mm/slub.c:3146 put_cpu_partial+0x17c/0x250 mm/slub.c:3221 __slab_free+0x2ea/0x3d0 mm/slub.c:4450 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:4265 [inline] __kmalloc_noprof+0x1fc/0x400 mm/slub.c:4277 kmalloc_noprof include/linux/slab.h:882 [inline] tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x2b7/0x740 security/tomoyo/file.c:822 security_inode_getattr+0x130/0x330 security/security.c:2371 vfs_getattr+0x45/0x430 fs/stat.c:204 vfs_statx_path fs/stat.c:251 [inline] vfs_statx+0x199/0x490 fs/stat.c:315 vfs_fstatat+0x145/0x190 fs/stat.c:341 __do_sys_newfstatat fs/stat.c:505 [inline] __se_sys_newfstatat fs/stat.c:499 [inline] __x64_sys_newfstatat+0x11d/0x1a0 fs/stat.c:499 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: 0033:0x7f41b19165f4 RSP: 002b:00007fff04e6ef28 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00005627df9f56e0 RCX: 00007f41b19165f4 RDX: 00007fff04e6ef38 RSI: 00005627df9e5897 RDI: 00000000ffffff9c RBP: 000056280f0f1fb8 R08: 00062305ed946d00 R09: 7fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00062305ed946d00 R15: 00005627df9e9dca rcu: rcu_preempt kthread starved for 1721 jiffies! g43409 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:24912 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5315 [inline] __schedule+0x1895/0x4b30 kernel/sched/core.c:6675 __schedule_loop kernel/sched/core.c:6752 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6767 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2615 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.12.0-rc1-syzkaller-00031-ge32cde8d2bd7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:trace_netif_rx_entry+0x1/0x210 include/trace/events/net.h:257 Code: c7 c7 bc 18 1d 90 e8 7e 1b 6c f8 e9 74 ff ff ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 <41> 56 53 48 89 fb e8 44 6a 02 f8 0f 1f 44 00 00 e8 3a 6a 02 f8 65 RSP: 0018:ffffc900001e6870 EFLAGS: 00000246 RAX: ffffffff899270f1 RBX: ffff888058220500 RCX: ffff88801d6d8000 RDX: 0000000000000100 RSI: 0000000000000300 RDI: ffff888058220500 RBP: 0000000000000300 R08: ffffffff899270e4 R09: 1ffffffff2039ccd R10: dffffc0000000000 R11: ffffffff86730e20 R12: ffff888058220558 R13: ffff888058220500 R14: 0000000000000028 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000005741f99c CR3: 000000005321c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __netif_rx+0x70/0xc0 net/core/dev.c:5210 loopback_xmit+0x454/0x6b0 drivers/net/loopback.c:89 __netdev_start_xmit include/linux/netdevice.h:4916 [inline] netdev_start_xmit include/linux/netdevice.h:4925 [inline] xmit_one net/core/dev.c:3588 [inline] dev_hard_start_xmit+0x27a/0x7e0 net/core/dev.c:3604 __dev_queue_xmit+0x1b58/0x3e80 net/core/dev.c:4424 dev_queue_xmit include/linux/netdevice.h:3094 [inline] neigh_hh_output include/net/neighbour.h:526 [inline] neigh_output include/net/neighbour.h:540 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236 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+0x4ad/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+0xc3/0x220 net/netfilter/core.c:626 nf_hook include/linux/netfilter.h:269 [inline] NF_HOOK+0x29e/0x450 include/linux/netfilter.h:312 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314 __netif_receive_skb_one_core net/core/dev.c:5662 [inline] __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5775 process_backlog+0x662/0x15b0 net/core/dev.c:6107 __napi_poll+0xcb/0x490 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x89b/0x1240 net/core/dev.c:6962 handle_softirqs+0x2c5/0x980 kernel/softirq.c:554 run_ksoftirqd+0xca/0x130 kernel/softirq.c:927 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244