rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P15212/1:b..l rcu: (detected by 1, t=10502 jiffies, g=58809, q=177 ncpus=2) task:syz.1.2271 state:R running task stack:28408 pid:15212 tgid:15202 ppid:5834 task_flags:0x400040 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7108 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:on_stack arch/x86/include/asm/stacktrace.h:60 [inline] RIP: 0010:stack_access_ok+0x7e/0x200 arch/x86/kernel/unwind_orc.c:393 Code: 85 52 01 00 00 48 89 da 48 8b 4b 10 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 0b 01 00 00 <8b> 13 85 d2 74 23 49 39 ef 77 1e 48 39 e9 76 19 4a 8d 54 25 00 49 RSP: 0018:ffffc9000c787418 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000c787518 RCX: ffffc9000c788000 RDX: 1ffff920018f0ea3 RSI: ffffc9000c787510 RDI: ffffc9000c787518 RBP: ffffc9000c787510 R08: ffffffff913e7dae R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000006aed R12: 0000000000000008 R13: ffffc9000c787528 R14: ffffc9000c787520 R15: ffffc9000c780000 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] unwind_next_frame+0xb7d/0x20a0 arch/x86/kernel/unwind_orc.c:585 __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24 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 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kmalloc_noprof+0x223/0x510 mm/slub.c:4340 kmalloc_noprof include/linux/slab.h:909 [inline] sock_kmalloc+0x111/0x170 net/core/sock.c:2884 hash_alloc_result+0xd7/0x150 crypto/algif_hash.c:41 hash_recvmsg+0x198/0x960 crypto/algif_hash.c:196 hash_recvmsg_nokey+0x66/0x90 crypto/algif_hash.c:350 sock_recvmsg_nosec net/socket.c:1017 [inline] ____sys_recvmsg+0x5f9/0x6b0 net/socket.c:2784 ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828 do_recvmmsg+0x2fe/0x750 net/socket.c:2923 __sys_recvmmsg net/socket.c:2997 [inline] __do_sys_recvmmsg net/socket.c:3020 [inline] __se_sys_recvmmsg net/socket.c:3013 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013 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: 0033:0x7f90a1d8e929 RSP: 002b:00007f90a2c45038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f90a1fb6160 RCX: 00007f90a1d8e929 RDX: 000000000000049f RSI: 0000200000006100 RDI: 000000000000000a RBP: 00007f90a1e10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f90a1fb6160 R15: 00007fff42477308 rcu: rcu_preempt kthread starved for 10496 jiffies! g58809 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:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 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: 1 UID: 0 PID: 13441 Comm: kworker/u8:10 Not tainted 6.16.0-rc4-syzkaller-00308-ga79a588fc176 #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:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xd7b/0x1510 kernel/smp.c:885 Code: e8 2a 1a 0c 00 45 85 ed 74 46 48 8b 14 24 49 89 d6 49 89 d5 49 c1 ee 03 41 83 e5 07 4d 01 e6 41 83 c5 03 e8 c7 1e 0c 00 f3 90 <41> 0f b6 06 41 38 c5 7c 08 84 c0 0f 85 6f 05 00 00 8b 43 08 31 ff RSP: 0018:ffffc90004a478a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b84421e0 RCX: ffffffff81b001dd RDX: ffff88801db3a440 RSI: ffffffff81b001b9 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed101708843d R15: ffff8880b853b580 FS: 0000000000000000(0000) GS:ffff888124815000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8cc48e56c0 CR3: 000000000e382000 CR4: 00000000003526f0 Call Trace: 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:2691 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2901 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+0x9cf/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