rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6566 rcu: (detected by 1, t=10503 jiffies, g=18621, q=912 ncpus=2) task:syz.1.27 state:R running task stack:26120 pid:6566 tgid:6565 ppid:6347 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 45 b5 0f 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 c1 22 7b 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d be 4e 73 RSP: 0018:ffffc90002517478 EFLAGS: 00000286 RAX: 40a425c44c262d00 RBX: 0000000000000246 RCX: 0000000000000046 RDX: 000000005a44979c RSI: ffffffff8e19b8e3 RDI: ffffffff8c27ca80 RBP: 0000000000000000 R08: ffffffff81767e95 R09: ffffffff8e75e620 R10: ffffc900025175d8 R11: ffffffff81b0cfd0 R12: 0000000000000002 R13: ffffffff8e75e620 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] kmem_cache_alloc_lru_noprof+0x2b8/0x640 mm/slub.c:4885 __d_alloc+0x37/0x6f0 fs/dcache.c:1740 d_alloc_pseudo+0x21/0xc0 fs/dcache.c:1871 alloc_path_pseudo fs/file_table.c:364 [inline] alloc_file_pseudo+0xdd/0x240 fs/file_table.c:380 __anon_inode_getfile fs/anon_inodes.c:166 [inline] anon_inode_getfile+0xc5/0x1a0 fs/anon_inodes.c:204 bpf_link_prime+0xfc/0x220 kernel/bpf/syscall.c:3449 bpf_raw_tp_link_attach+0x4c4/0x700 kernel/bpf/syscall.c:4275 bpf_raw_tracepoint_open+0x1b2/0x220 kernel/bpf/syscall.c:4312 __sys_bpf+0x846/0x950 kernel/bpf/syscall.c:6270 __do_sys_bpf kernel/bpf/syscall.c:6341 [inline] __se_sys_bpf kernel/bpf/syscall.c:6339 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6339 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5d1559aef9 RSP: 002b:00007f5d1647f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f5d15805fa0 RCX: 00007f5d1559aef9 RDX: 0000000000000010 RSI: 0000200000000540 RDI: 0000000000000011 RBP: 00007f5d1562fee0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5d15806038 R14: 00007f5d15805fa0 R15: 00007fff61200f58 rcu: rcu_preempt kthread starved for 2405 jiffies! g18621 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:27656 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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: 6362 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:__sanitizer_cov_trace_switch+0x37/0x130 kernel/kcov.c:334 Code: c1 f8 48 c1 c1 3d 48 83 f9 02 7f 1e 48 85 c9 74 3c 48 83 f9 01 0f 85 f3 00 00 00 b9 03 00 00 00 48 85 c0 75 36 e9 e4 00 00 00 <48> 83 f9 03 0f 84 cc 00 00 00 48 83 f9 07 0f 85 d0 00 00 00 b9 07 RSP: 0018:ffffc900034c7108 EFLAGS: 00000002 RAX: 0000000000000020 RBX: 0000000000000004 RCX: 0000000000000003 RDX: 0000000000000000 RSI: ffffffff8e7beb00 RDI: 0000000000000004 RBP: 000000000000053c R08: ffff88802fdddb80 R09: 0000000000000020 R10: 000000000000001f R11: 0000000000000000 R12: dffffc0000000000 R13: 000000000000053c R14: ffff88813fe4e54c R15: 0000000000083944 FS: 0000000000000000(0000) GS:ffff888125455000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000012a3669a3638 CR3: 000000004687c000 CR4: 00000000003526f0 Call Trace: rb_event_length+0x45/0x400 kernel/trace/ring_buffer.c:223 rb_read_data_buffer+0xdf/0x5a0 kernel/trace/ring_buffer.c:1863 check_buffer+0x28a/0x750 kernel/trace/ring_buffer.c:4435 __rb_reserve_next+0x5c5/0xe00 kernel/trace/ring_buffer.c:4534 rb_reserve_next_event kernel/trace/ring_buffer.c:4671 [inline] ring_buffer_lock_reserve+0xbb5/0x1010 kernel/trace/ring_buffer.c:4730 __trace_buffer_lock_reserve kernel/trace/trace.h:1609 [inline] trace_event_buffer_lock_reserve+0x1d2/0x700 kernel/trace/trace.c:2392 trace_event_buffer_reserve+0x1ef/0x2d0 kernel/trace/trace_events.c:688 do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_event_raw_event_bpf_trace_printk+0x11c/0x2c0 kernel/trace/bpf_trace.h:11 __do_trace_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline] trace_bpf_trace_printk+0x187/0x200 kernel/trace/bpf_trace.h:11 ____bpf_trace_printk kernel/trace/bpf_trace.c:379 [inline] bpf_trace_printk+0x141/0x1c0 kernel/trace/bpf_trace.c:362 bpf_prog_b1367f0be6c54012+0x39/0x3f bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2088 [inline] bpf_trace_run1+0x36f/0x830 kernel/trace/bpf_trace.c:2128 __bpf_trace_rcu_utilization+0xb4/0x100 include/trace/events/rcu.h:27 __traceiter_rcu_utilization+0x7a/0xb0 include/trace/events/rcu.h:27 __do_trace_rcu_utilization include/trace/events/rcu.h:27 [inline] trace_rcu_utilization+0x1c4/0x200 include/trace/events/rcu.h:27 rcu_note_context_switch+0x6e/0xf40 kernel/rcu/tree_plugin.h:330 __schedule+0x304/0x52d0 kernel/sched/core.c:6794 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7095 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] _raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194 mm_destroy_cid include/linux/mm_types.h:1555 [inline] __mmdrop+0x420/0x750 kernel/fork.c:734 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 __do_sys_exit_group kernel/exit.c:1129 [inline] __se_sys_exit_group kernel/exit.c:1127 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1127 x64_sys_call+0x221a/0x2240 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f97f72f16c5 Code: Unable to access opcode bytes at 0x7f97f72f169b. RSP: 002b:00007ffedfbe02a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00005598dfa1f590 RCX: 00007f97f72f16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 00005598df9ff910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffedfbe02f0 R14: 0000000000000000 R15: 0000000000000000