rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P20723/1:b..l rcu: (detected by 0, t=10502 jiffies, g=134473, q=228 ncpus=2) task:syz-executor state:R running task stack:23208 pid:20723 tgid:20723 ppid:20684 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7104 irqentry_exit+0x36/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:unwind_next_frame+0x159d/0x20a0 arch/x86/kernel/unwind_orc.c:648 Code: 10 49 89 f8 41 83 e0 07 44 38 c6 41 0f 9e c0 40 84 f6 40 0f 95 c6 41 84 f0 0f 85 01 0a 00 00 83 e0 07 38 c2 40 0f 9e c6 84 d2 <0f> 95 c0 40 84 c6 0f 85 ea 09 00 00 48 0f bf 69 02 ba 08 00 00 00 RSP: 0018:ffffc90003e378b8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff9149da66 RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff9149da68 RBP: ffffc90003e37970 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 00000000000117e6 R12: ffffc90003e37978 R13: ffffc90003e37928 R14: ffffc90003e37d20 R15: ffffc90003e3795c arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:319 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:345 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4147 [inline] slab_alloc_node mm/slub.c:4196 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4203 sk_prot_alloc+0x60/0x2a0 net/core/sock.c:2241 sk_alloc+0x36/0xc20 net/core/sock.c:2303 inet6_create net/ipv6/af_inet6.c:193 [inline] inet6_create+0x381/0x1300 net/ipv6/af_inet6.c:120 __sock_create+0x335/0x8d0 net/socket.c:1541 sock_create net/socket.c:1599 [inline] __sys_socket_create net/socket.c:1636 [inline] __sys_socket+0x14d/0x260 net/socket.c:1683 __do_sys_socket net/socket.c:1697 [inline] __se_sys_socket net/socket.c:1695 [inline] __x64_sys_socket+0x72/0xb0 net/socket.c:1695 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f37e3f90887 RSP: 002b:00007ffff94aaa58 EFLAGS: 00000206 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f37e3f90887 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 000000000000000a RBP: 00007ffff94ab18c R08: 00007ffff94aaa7c R09: 0079746972756365 R10: 00007ffff94aaae0 R11: 0000000000000206 R12: 00007f37e417ec80 R13: 00000000000927c0 R14: 0000000000225149 R15: 00007f37e4180e40 rcu: rcu_preempt kthread starved for 10500 jiffies! g134473 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:28360 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 26516 Comm: kworker/u8:16 Not tainted 6.15.0-syzkaller-09161-g0f70f5b08a47 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x0/0x20 kernel/kcov.c:313 Code: 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 58 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 89 f2 89 fe bf 05 00 00 00 e9 2a fe ff ff RSP: 0018:ffffc90004107898 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b85416a0 RCX: ffffffff81afd49d RDX: ffff88801d2c2440 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed10170a82d5 R15: ffff8880b843cfc0 FS: 0000000000000000(0000) GS:ffff88812476e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000000e382000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xd2d/0x1490 kernel/smp.c:885 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2660 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2870 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 vkms_vblank_simulate: vblank timer overrun