rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-....: (1 GPs behind) idle=2d7c/1/0x4000000000000002 softirq=55384/55386 fqs=589 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P14981 (detected by 0, t=10502 jiffies, g=65893, q=774 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14981 Comm: syz.0.3435 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x7a/0x80 kernel/kcov.c:322 Code: c1 e1 05 4c 8d 51 28 4d 39 ca 77 1e 49 ff c0 4c 89 02 48 c7 44 0a 08 07 00 00 00 48 89 7c 0a 10 48 89 74 0a 18 48 89 44 0a 20 0f 1f 44 00 00 48 8b 46 08 48 8d 48 ff 48 89 c2 48 31 ca 48 39 RSP: 0018:ffffc900001e0618 EFLAGS: 00000046 RAX: ffffffff81a4c41c RBX: 0000000000000010 RCX: ffff88807b8a8000 RDX: 0000000000000100 RSI: 0000000000080000 RDI: 0000000000000000 RBP: ffffc900001e0710 R08: ffff88807b8a8007 R09: 1ffff1100f715000 R10: dffffc0000000000 R11: ffffed100f715001 R12: 1ffff9200003c154 R13: ffff888077e0bc00 R14: 00000000000f250c R15: dffffc0000000000 FS: 00007f8eb41b86c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005555762e3a38 CR3: 000000005e825000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: perf_prepare_sample+0xffc/0x2020 kernel/events/core.c:7659 __perf_event_output kernel/events/core.c:7730 [inline] perf_event_output_forward+0x197/0x2f0 kernel/events/core.c:7750 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9496 perf_swevent_overflow kernel/events/core.c:9579 [inline] perf_swevent_event+0x315/0x570 kernel/events/core.c:9630 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10064 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline] RIP: 0010:handle_softirqs+0x1b7/0x910 kernel/softirq.c:584 Code: 89 7c 24 2c 0f b7 db 48 c7 c7 00 0e 8b 8a e8 b0 cd e1 08 65 66 c7 05 66 62 b4 7e 00 00 e8 b1 59 39 00 fb 49 c7 c5 c0 a0 80 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c6 41 ff c6 0f 84 RSP: 0018:ffffc900001e0e20 EFLAGS: 00000282 RAX: f8c10b974c56b400 RBX: 0000000000000200 RCX: f8c10b974c56b400 RDX: dffffc0000000000 RSI: ffffffff8a8c1820 RDI: ffffffff8adf6120 RBP: ffffc900001e0f30 R08: ffff8880b8f3580b R09: 1ffff110171e6b01 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: dffffc0000000000 R13: ffffffff8c80a0c0 R14: ffff88807b8a8000 R15: 000000000000000a __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__rcu_read_unlock+0x36/0xd0 kernel/rcu/tree_plugin.h:425 Code: 00 00 00 00 fc ff df 65 48 8b 3d 35 7d 95 7e 48 8d 9f 3c 04 00 00 49 89 dc 49 c1 ec 03 43 0f b6 04 3c 84 c0 75 48 ff 0b 75 1d <4c> 8d b7 40 04 00 00 4c 89 f0 48 c1 e8 03 42 0f b6 04 38 84 c0 75 RSP: 0018:ffffc900065d7868 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88807b8a843c RCX: 0000000000080000 RDX: ffffc90005a79000 RSI: 0000000000024682 RDI: ffff88807b8a8000 RBP: dffffc0000000000 R08: ffff88801ad8bfbf R09: 1ffff110035b17f7 R10: dffffc0000000000 R11: ffffed10035b17f8 R12: 1ffff1100f715087 R13: 0000000000000003 R14: 0000000000000000 R15: dffffc0000000000 rcu_read_unlock include/linux/rcupdate.h:823 [inline] page_ext_put+0x91/0xb0 mm/page_ext.c:182 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1487 [inline] free_pcp_prepare mm/page_alloc.c:1537 [inline] free_unref_page_prepare+0x8e5/0x9e0 mm/page_alloc.c:3414 free_unref_page+0x2e/0x3f0 mm/page_alloc.c:3509 free_slab mm/slub.c:2036 [inline] discard_slab mm/slub.c:2042 [inline] __unfreeze_partials+0x188/0x1e0 mm/slub.c:2591 put_cpu_partial+0x17c/0x250 mm/slub.c:2667 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] __kmem_cache_alloc_node+0x19d/0x270 mm/slub.c:3398 __do_kmalloc_node mm/slab_common.c:935 [inline] __kmalloc+0xa3/0x240 mm/slab_common.c:949 kmalloc include/linux/slab.h:568 [inline] tomoyo_realpath_from_path+0xe2/0x5c0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x22f/0x650 security/tomoyo/file.c:723 security_file_ioctl+0x6c/0xa0 security/security.c:1572 __do_sys_ioctl fs/ioctl.c:864 [inline] __se_sys_ioctl+0x48/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8eb339e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8eb41b8028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f8eb3625fa0 RCX: 00007f8eb339e0d9 RDX: 0000200000000040 RSI: 0000000000008955 RDI: 000000000000000a RBP: 00007f8eb3435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8eb3626038 R14: 00007f8eb3625fa0 R15: 00007ffde55e33c8 task:syz.0.3435 state:R running task stack:22960 pid:14981 ppid:12917 flags:0x00004008 Call Trace: rcu: rcu_preempt kthread starved for 316 jiffies! g65893 f0x0 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:27888 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5246 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6563 schedule+0xb9/0x180 kernel/sched/core.c:6639 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 14983 Comm: syz.1.3432 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:__stack_depot_save+0x48/0x480 lib/stackdepot.c:441 Code: 28 00 00 00 48 89 44 24 28 48 c7 44 24 20 00 00 00 00 e8 3b 8b 33 fd 89 c1 31 c0 85 c9 0f 84 54 01 00 00 80 3d 09 ef ba 12 00 <0f> 85 47 01 00 00 44 8d 04 09 8d 2c cd 7b 71 f5 75 41 83 f8 04 0f RSP: 0018:ffffc90000006e58 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000013 RDX: 0000000000000001 RSI: 0000000000000026 RDI: ffffc90000006ec0 RBP: ffffc900000070f0 R08: 0000000000000000 R09: 1ffffffff1c4221d R10: dffffc0000000000 R11: fffffbfff1c4221e R12: 0000000000000000 R13: 1ffff92000000e34 R14: ffffc90000006ec0 R15: 0000000000000800 FS: 00007f44fe2266c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1f93def2f8 CR3: 0000000063a88000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: kasan_save_stack+0x4c/0x60 mm/kasan/common.c:47 __kasan_record_aux_stack+0xb2/0xc0 mm/kasan/generic.c:486 call_rcu+0x14f/0x950 kernel/rcu/tree.c:2849 refdst_drop include/net/dst.h:256 [inline] skb_dst_drop include/net/dst.h:268 [inline] skb_release_head_state+0x6d/0x240 net/core/skbuff.c:840 skb_release_all net/core/skbuff.c:854 [inline] __kfree_skb net/core/skbuff.c:870 [inline] kfree_skb_reason+0x133/0x370 net/core/skbuff.c:893 kfree_skb include/linux/skbuff.h:1252 [inline] ip6_tnl_start_xmit+0xbe5/0x1290 net/ipv6/ip6_tunnel.c:1465 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3695 [inline] dev_hard_start_xmit+0x292/0x8b0 net/core/dev.c:3711 __dev_queue_xmit+0x1b4b/0x3810 net/core/dev.c:4375 neigh_output include/net/neighbour.h:549 [inline] ip6_finish_output2+0xdc6/0x15c0 net/ipv6/ip6_output.c:138 dst_output include/net/dst.h:453 [inline] NF_HOOK include/linux/netfilter.h:302 [inline] ndisc_send_skb+0xc04/0x1520 net/ipv6/ndisc.c:513 addrconf_rs_timer+0x367/0x640 net/ipv6/addrconf.c:3986 call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x56c/0x810 kernel/time/timer.c:2023 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x291/0x910 kernel/softirq.c:596 __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:__phys_addr+0x8/0x170 arch/x86/mm/physaddr.c:16 Code: 4c 89 ff 31 f6 e8 b8 69 8e 00 b8 01 00 00 00 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d c3 00 00 cc cc 41 57 41 56 53 48 89 fb 23 46 48 00 48 bf ff ff ff 7f ff ff ff ff 48 89 de e8 f1 49 48 RSP: 0018:ffffc9000661ed40 EFLAGS: 00000a02 RAX: 1ffff1100b1b3580 RBX: ffff888058d9ac00 RCX: 0000000000000000 RDX: ffffffff81d3775b RSI: ffff888058d9ac00 RDI: ffff888058d9ac00 RBP: ffff888058d9ae00 R08: ffff8880b8e3580b R09: 1ffff110171c6b01 R10: dffffc0000000000 R11: ffffed10171c6b02 R12: ffff8880174c5000 R13: dffffc0000000000 R14: ffffffff81d3775b R15: ffff8880174c5000 virt_to_folio include/linux/mm.h:913 [inline] virt_to_slab mm/slab.h:175 [inline] ___cache_free+0x16/0x160 mm/slub.c:3694 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x76/0xe0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x144/0x160 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x1e/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook+0x4b/0x490 mm/slab.h:737 slab_alloc_node mm/slub.c:3359 [inline] __kmem_cache_alloc_node+0x19d/0x270 mm/slub.c:3398 kmalloc_node_trace+0x22/0xe0 mm/slab_common.c:1039 kmalloc_node include/linux/slab.h:585 [inline] kzalloc_node include/linux/slab.h:710 [inline] __get_vm_area_node+0x122/0x330 mm/vmalloc.c:2563 __vmalloc_node_range+0x357/0x1380 mm/vmalloc.c:3260 __vmalloc_node mm/vmalloc.c:3365 [inline] vmalloc+0x75/0x80 mm/vmalloc.c:3398 bpf_prog_calc_tag+0xde/0x660 kernel/bpf/core.c:288 resolve_pseudo_ldimm64+0xcc/0xfd0 kernel/bpf/verifier.c:13053 bpf_check+0x3d35/0x11000 kernel/bpf/verifier.c:15587 bpf_prog_load+0x100e/0x1530 kernel/bpf/syscall.c:2651 __sys_bpf+0x5b8/0x780 kernel/bpf/syscall.c:5032 __do_sys_bpf kernel/bpf/syscall.c:5136 [inline] __se_sys_bpf kernel/bpf/syscall.c:5134 [inline] __x64_sys_bpf+0x78/0x90 kernel/bpf/syscall.c:5134 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f44fd39e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f44fe226028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f44fd625fa0 RCX: 00007f44fd39e0d9 RDX: 0000000000000048 RSI: 00002000000017c0 RDI: 0000000000000005 RBP: 00007f44fd435024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f44fd626038 R14: 00007f44fd625fa0 R15: 00007ffc4568cf88