rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12040/1:b..l rcu: (detected by 1, t=10504 jiffies, g=74197, q=461 ncpus=2) task:syz.0.1648 state:R running task stack:23800 pid:12040 tgid:12039 ppid:5606 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7413 preempt_schedule_thunk+0x16/0x40 arch/x86/entry/thunk.S:12 __local_bh_enable_ip+0xff/0x120 kernel/softirq.c:457 local_bh_enable include/linux/bottom_half.h:33 [inline] xdp_test_run_batch.constprop.0+0x1433/0x1ca0 net/bpf/test_run.c:356 bpf_test_run_xdp_live+0x367/0x760 net/bpf/test_run.c:378 bpf_prog_test_run_xdp+0xd7d/0x1670 net/bpf/test_run.c:1463 bpf_prog_test_run kernel/bpf/syscall.c:4859 [inline] __sys_bpf+0x2a12/0x4e80 kernel/bpf/syscall.c:6436 __do_sys_bpf kernel/bpf/syscall.c:6537 [inline] __se_sys_bpf kernel/bpf/syscall.c:6534 [inline] __x64_sys_bpf+0xce/0x140 kernel/bpf/syscall.c:6534 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7febbcd9ce59 RSP: 002b:00007febbdc7a028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007febbd015fa0 RCX: 00007febbcd9ce59 RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a RBP: 00007febbce32e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007febbd016038 R14: 00007febbd015fa0 R15: 00007ffe089d4778 rcu: rcu_preempt kthread timer wakeup didn't happen for 10485 jiffies! g74197 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=40032 rcu: rcu_preempt kthread starved for 10486 jiffies! g74197 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28824 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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: 5271 Comm: dhcpcd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x0/0x20 kernel/kcov.c:299 Code: 0c 24 48 89 f2 48 89 fe bf 06 00 00 00 e9 b8 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 0c 24 40 0f b6 d6 40 0f b6 f7 bf 01 00 00 00 e9 RSP: 0018:ffffc90000007e48 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880284f8300 RCX: ffffffff81f513b0 RDX: 1ffff1100509f067 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffff8880b8428540 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880b8428400 R14: 0000000000000001 R15: 0000000000000000 FS: 00007fbc44d2e780(0000) GS:ffff8881240e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c375cb0 CR3: 0000000076583000 CR4: 00000000003526f0 Call Trace: __remove_hrtimer+0xc1/0x440 kernel/time/hrtimer.c:1147 __run_hrtimer kernel/time/hrtimer.c:2012 [inline] __hrtimer_run_queues+0x352/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x6/0x310 kernel/locking/lockdep.c:5876 Code: 4c 24 18 4c 8b 54 24 10 44 8b 5c 24 0c eb 98 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 <41> 56 41 54 55 53 48 89 fb 48 83 ec 18 65 48 8b 2d 3d ea 4e 12 48 RSP: 0018:ffffc90002fa7b38 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff82bddbd9 RDX: ffff888028c4a540 RSI: ffffffff82bddb2e RDI: ffffffff8e9e60c0 RBP: ffff88801ce87800 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001 R13: ffff888029d28870 R14: ffff88802228f3c0 R15: ffffc90002fa7cc0 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] kernfs_root+0xf3/0x2a0 fs/kernfs/kernfs-internal.h:76 kernfs_root_is_locked fs/kernfs/kernfs-internal.h:110 [inline] kernfs_parent fs/kernfs/kernfs-internal.h:134 [inline] kernfs_dop_revalidate+0x516/0x7e0 fs/kernfs/dir.c:1223 d_revalidate fs/namei.c:1035 [inline] d_revalidate fs/namei.c:1031 [inline] lookup_fast+0x3c7/0x600 fs/namei.c:1881 walk_component fs/namei.c:2278 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x1dc/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 do_readlinkat+0xd3/0x370 fs/stat.c:571 __do_sys_readlink fs/stat.c:605 [inline] __se_sys_readlink fs/stat.c:602 [inline] __x64_sys_readlink+0x78/0xc0 fs/stat.c:602 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbc44e263a7 Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 8a 20 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 21 ba 0d 00 f7 d8 64 89 02 48 RSP: 002b:00007ffd03ff5df8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059 RAX: ffffffffffffffda RBX: 00007ffd03ff62d0 RCX: 00007fbc44e263a7 RDX: 0000000000000400 RSI: 00007ffd03ff5e00 RDI: 00007ffd03ff62d0 RBP: 00007ffd03ff5e00 R08: 00007fbc44d1e3cc R09: 00007ffd040073e0 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400 R13: 00005580c5f46850 R14: 00007ffd03ff6b00 R15: 00007ffd04007350