rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P26213/1:b.el rcu: (detected by 1, t=10503 jiffies, g=180357, q=520 ncpus=2) task:syz.4.5837 state:R running task stack:23656 pid:26213 ppid:23829 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 __local_bh_enable_ip+0x14b/0x1c0 kernel/softirq.c:413 local_bh_enable include/linux/bottom_half.h:33 [inline] xdp_test_run_batch net/bpf/test_run.c:361 [inline] bpf_test_run_xdp_live+0x18bc/0x1b20 net/bpf/test_run.c:383 bpf_prog_test_run_xdp+0x7ca/0x10e0 net/bpf/test_run.c:1326 bpf_prog_test_run+0x321/0x390 kernel/bpf/syscall.c:4132 __sys_bpf+0x49d/0x890 kernel/bpf/syscall.c:5495 __do_sys_bpf kernel/bpf/syscall.c:5581 [inline] __se_sys_bpf kernel/bpf/syscall.c:5579 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5579 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f02ded9ce59 RSP: 002b:00007f02dfc76028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f02df015fa0 RCX: 00007f02ded9ce59 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007f02dee32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f02df016038 R14: 00007f02df015fa0 R15: 00007ffe9531d218 rcu: rcu_preempt kthread starved for 250 jiffies! g180357 f0x0 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:26568 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0x1553/0x45a0 kernel/sched/core.c:6700 schedule+0xbd/0x170 kernel/sched/core.c:6774 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 PID: 26227 Comm: syz.6.5840 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:234 Code: f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 40 8a 7c 7e 65 8b RSP: 0018:ffffc900001f03d8 EFLAGS: 00000246 RAX: ffffffff813b363c RBX: ffffc900001f0408 RCX: ffff88803216bc00 RDX: 0000000000000100 RSI: 0000000000000101 RDI: ffffc900001f0408 RBP: ffffc900001f0490 R08: ffff88803216bc00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000100 R12: ffffffff8175c6fa R13: 00000000000000e8 R14: dffffc0000000000 R15: ffffc900001f0408 FS: 00007f6b47bd56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005654c601d168 CR3: 00000000684e9000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000200000000300 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: unwind_get_return_address+0x1c/0xc0 arch/x86/kernel/unwind_orc.c:365 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:46 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:53 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:329 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x11a/0x2d0 mm/slub.c:3519 dst_alloc+0x105/0x170 net/core/dst.c:90 ip6_dst_alloc net/ipv6/route.c:344 [inline] icmp6_dst_alloc+0x7b/0x400 net/ipv6/route.c:3317 ndisc_send_skb+0x44e/0x14f0 net/ipv6/ndisc.c:493 addrconf_rs_timer+0x2d5/0x630 net/ipv6/addrconf.c:4024 call_timer_fn+0x189/0x540 kernel/time/timer.c:1701 expire_timers kernel/time/timer.c:1752 [inline] __run_timers+0x542/0x800 kernel/time/timer.c:2023 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2036 handle_softirqs+0x280/0x820 kernel/softirq.c:578 __do_softirq kernel/softirq.c:612 [inline] invoke_softirq kernel/softirq.c:452 [inline] __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:preempt_schedule_irq+0xba/0x150 kernel/sched/core.c:7010 Code: 00 00 43 c6 44 37 04 f8 74 0b 0f 0b 48 f7 03 08 00 00 00 74 6f bf 01 00 00 00 e8 a1 ea cb f6 e8 4c fd fc f6 fb bf 01 00 00 00 f1 b4 ff ff 43 c6 44 37 08 00 48 c7 44 24 40 00 00 00 00 9c 8f RSP: 0018:ffffc9000fcef180 EFLAGS: 00000282 RAX: c9a1b88c2c9be300 RBX: 0000000000000000 RCX: c9a1b88c2c9be300 RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: 0000000000000001 RBP: ffffc9000fcef220 R08: ffffffff911cd52f R09: 1ffffffff2239aa5 R10: dffffc0000000000 R11: fffffbfff2239aa6 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92001f9de30 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:save_stack+0x16b/0x230 mm/page_owner.c:133 Code: f6 74 15 e8 f7 8b 9e ff eb 1a e8 f0 8b 9e ff 44 8b 35 d9 37 4b 15 eb 1e e8 e2 8b 9e ff 44 8b 35 eb 37 4b 15 43 0f b6 44 25 00 <84> c0 0f 85 9d 00 00 00 80 63 01 f7 48 b8 f8 f8 f8 f8 f8 f8 f8 f8 RSP: 0018:ffffc9000fcef2e0 EFLAGS: 00000287 RAX: 0000000000000000 RBX: ffff88803216c170 RCX: 0000000000080000 RDX: ffffc90011571000 RSI: 0000000000025913 RDI: 0000000000025914 RBP: ffffc9000fcef410 R08: 0000000088497b4c R09: 00000000bbb9301c R10: 0000000000000004 R11: 0000000000000002 R12: dffffc0000000000 R13: 1ffff1100642d82e R14: 00000000073901b3 R15: 1ffff92001f9de60 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1181 [inline] free_unref_page_prepare+0x7b2/0x8c0 mm/page_alloc.c:2365 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2458 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6e/0x4b0 mm/slab.h:767 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc_lru+0x111/0x2d0 mm/slub.c:3526 __d_alloc+0x31/0x730 fs/dcache.c:1773 d_alloc fs/dcache.c:1853 [inline] d_alloc_parallel+0xe0/0x1530 fs/dcache.c:2646 lookup_open fs/namei.c:3421 [inline] open_last_lookups fs/namei.c:3564 [inline] path_openat+0x933/0x3230 fs/namei.c:3794 do_filp_open+0x1f5/0x430 fs/namei.c:3824 do_sys_openat2+0x134/0x1d0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6b4999ce59 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:00007f6b47bd5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f6b49c16090 RCX: 00007f6b4999ce59 RDX: 00000000000026e1 RSI: 0000200000000300 RDI: ffffffffffffff9c RBP: 00007f6b49a32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6b49c16128 R14: 00007f6b49c16090 R15: 00007ffedb81cde8