rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=d954/1/0x4000000000000002 softirq=21534/21534 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7124 (detected by 0, t=10502 jiffies, g=26161, q=485 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7124 Comm: syz.0.726 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:perf_prepare_sample+0x16a/0x2020 kernel/events/core.c:7535 Code: 30 66 41 09 07 4c 8b 7c 24 18 4c 89 f8 48 c1 e8 03 48 89 44 24 48 42 80 3c 20 00 4c 8b 74 24 10 74 08 4c 89 ff e8 c6 ae 2e 00 <4d> 8b 2f 4c 89 6c 24 20 49 f7 d5 4d 21 f5 48 89 df 4c 89 fe 48 8b RSP: 0018:ffffc900001e0580 EFLAGS: 00000046 RAX: 1ffff9200003c138 RBX: ffffc900001e0720 RCX: 0000000000000000 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc900001e0670 R08: ffffc900001e06f7 R09: ffffc900001e06c0 R10: dffffc0000000000 R11: fffff5200003c0df R12: dffffc0000000000 R13: ffff888026d0d400 R14: 00000000000002d0 R15: ffffc900001e09c0 FS: 00007f2073dec6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000058799000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __perf_event_output kernel/events/core.c:7730 [inline] perf_event_output_forward+0x197/0x2f0 kernel/events/core.c:7750 __perf_event_overflow+0x457/0x630 kernel/events/core.c:9496 perf_swevent_overflow+0x19b/0x230 kernel/events/core.c:9579 perf_swevent_event+0x458/0x570 kernel/events/core.c:-1 perf_tp_event+0x36b/0xc10 kernel/events/core.c:10064 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10032 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14 trace_irq_disable include/trace/events/preemptirq.h:36 [inline] trace_hardirqs_off_finish+0x13f/0x180 kernel/trace/trace_preemptirq.c:67 irqentry_enter+0x33/0x50 kernel/entry/common.c:382 sysvec_irq_work+0xa/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline] RIP: 0010:handle_softirqs+0x1b7/0x910 kernel/softirq.c:584 Code: 89 7c 24 2c 0f b7 db 48 c7 c7 80 0d 8b 8a e8 e0 1f e1 08 65 66 c7 05 66 62 b4 7e 00 00 e8 91 46 39 00 fb 49 c7 c5 c0 a0 80 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c6 41 ff c6 0f 84 RSP: 0018:ffffc900001e0e20 EFLAGS: 00000282 RAX: 827dddaecd585500 RBX: 0000000000000200 RCX: 827dddaecd585500 RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf42e0 RBP: ffffc900001e0f30 R08: ffff8880b8f3580b R09: 1ffff110171e6b01 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: dffffc0000000000 R13: ffffffff8c80a0c0 R14: ffff88802b560000 R15: 000000000000000a __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:rcu_read_unlock_special+0x0/0x510 kernel/rcu/tree_plugin.h:630 Code: 26 5b 66 00 eb b0 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 94 49 89 fd 4c 89 f7 e8 0c 5b 66 00 4c 89 ef eb 84 0f 1f 80 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 RSP: 0018:ffffc90003887ad0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88802b56043c RCX: 827dddaecd585500 RDX: 0000000000000001 RSI: ffffffff8adf42c0 RDI: ffff88802b560000 RBP: 1ffff1100ef26572 R08: ffffffff8e2121af R09: 1ffffffff1c42435 R10: dffffc0000000000 R11: fffffbfff1c42436 R12: 1ffff110056ac087 R13: dffffc0000000000 R14: ffff88802b560440 R15: dffffc0000000000 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:823 [inline] get_mem_cgroup_from_objcg+0x12d/0x150 include/linux/memcontrol.h:525 obj_cgroup_charge_pages mm/memcontrol.c:3097 [inline] obj_cgroup_charge+0x358/0x620 mm/memcontrol.c:3390 memcg_slab_pre_alloc_hook mm/slab.h:501 [inline] slab_pre_alloc_hook+0x2e2/0x300 mm/slab.h:715 slab_alloc_node mm/slub.c:3279 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x56/0x2f0 mm/slub.c:3383 kmem_cache_zalloc include/linux/slab.h:689 [inline] __alloc_file+0x25/0x230 fs/file_table.c:138 alloc_empty_file+0x90/0x180 fs/file_table.c:187 alloc_file+0x5b/0x5f0 fs/file_table.c:229 alloc_file_pseudo+0x180/0x200 fs/file_table.c:272 sock_alloc_file+0xb3/0x240 net/socket.c:467 sock_map_fd net/socket.c:491 [inline] __sys_socket+0x12d/0x190 net/socket.c:1679 __do_sys_socket net/socket.c:1684 [inline] __se_sys_socket net/socket.c:1682 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1682 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f2072f9de99 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:00007f2073dec028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f2073225fa0 RCX: 00007f2072f9de99 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 000000000000000a RBP: 00007f2073033eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2073226038 R14: 00007f2073225fa0 R15: 00007fffe597a8d8 task:syz.0.726 state:R running task stack:22736 pid:7124 ppid:4279 flags:0x0000400c Call Trace: rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g26161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=12514 rcu: rcu_preempt kthread starved for 10502 jiffies! g26161 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26800 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7124 Comm: syz.0.726 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13 Code: 80 a1 bc 8c 4c 89 f6 e8 8d a7 0c fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 80 42 df 8a 48 c7 c6 c0 42 df 8a eb 00 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc900001e07f0 EFLAGS: 00000046 RAX: 1ffff110056ac15a RBX: 7e8285bf9ccb5258 RCX: 0000000000000001 RDX: 0000000000000002 RSI: ffffffff8a8c2920 RDI: ffffffff8adf42e0 RBP: ffffc900001e0910 R08: ffffffff8e2121af R09: 1ffffffff1c42435 R10: dffffc0000000000 R11: fffffbfff1c42436 R12: ffff88802b560b30 R13: dffffc0000000000 R14: ffff88802b560ad0 R15: 1ffff9200003c10c FS: 00007f2073dec6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000058799000 CR4: 00000000003506e0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_release+0x558/0x920 kernel/locking/lockdep.c:5698 rcu_lock_release include/linux/rcupdate.h:355 [inline] rcu_read_unlock_sched include/linux/rcupdate.h:904 [inline] pfn_valid include/linux/mmzone.h:1867 [inline] __virt_addr_valid+0x435/0x540 arch/x86/mm/physaddr.c:65 kasan_addr_to_slab+0x9/0xc0 mm/kasan/common.c:36 __kasan_record_aux_stack+0xf/0xc0 mm/kasan/generic.c:471 irq_work_queue_on+0x10f/0x260 kernel/irq_work.c:140 rcu_read_unlock_special+0x3c9/0x510 kernel/rcu/tree_plugin.h:678 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:823 [inline] trace_call_bpf+0x5bb/0x6b0 kernel/trace/bpf_trace.c:137 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:10027 perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728 RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:319 [inline] RIP: 0010:handle_softirqs+0x1b7/0x910 kernel/softirq.c:584 Code: 89 7c 24 2c 0f b7 db 48 c7 c7 80 0d 8b 8a e8 e0 1f e1 08 65 66 c7 05 66 62 b4 7e 00 00 e8 91 46 39 00 fb 49 c7 c5 c0 a0 80 8c <89> 5c 24 34 b8 ff ff ff ff 0f bc 44 24 34 41 89 c6 41 ff c6 0f 84 RSP: 0018:ffffc900001e0e20 EFLAGS: 00000282 RAX: 827dddaecd585500 RBX: 0000000000000200 RCX: 827dddaecd585500 RDX: dffffc0000000000 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf42e0 RBP: ffffc900001e0f30 R08: ffff8880b8f3580b R09: 1ffff110171e6b01 R10: dffffc0000000000 R11: ffffed10171e6b02 R12: dffffc0000000000 R13: ffffffff8c80a0c0 R14: ffff88802b560000 R15: 000000000000000a __do_softirq kernel/softirq.c:630 [inline] invoke_softirq kernel/softirq.c:470 [inline] __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:rcu_read_unlock_special+0x0/0x510 kernel/rcu/tree_plugin.h:630 Code: 26 5b 66 00 eb b0 44 89 f1 80 e1 07 80 c1 03 38 c1 7c 94 49 89 fd 4c 89 f7 e8 0c 5b 66 00 4c 89 ef eb 84 0f 1f 80 00 00 00 00 <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec c0 00 RSP: 0018:ffffc90003887ad0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffff88802b56043c RCX: 827dddaecd585500 RDX: 0000000000000001 RSI: ffffffff8adf42c0 RDI: ffff88802b560000 RBP: 1ffff1100ef26572 R08: ffffffff8e2121af R09: 1ffffffff1c42435 R10: dffffc0000000000 R11: fffffbfff1c42436 R12: 1ffff110056ac087 R13: dffffc0000000000 R14: ffff88802b560440 R15: dffffc0000000000 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426 rcu_read_unlock include/linux/rcupdate.h:823 [inline] get_mem_cgroup_from_objcg+0x12d/0x150 include/linux/memcontrol.h:525 obj_cgroup_charge_pages mm/memcontrol.c:3097 [inline] obj_cgroup_charge+0x358/0x620 mm/memcontrol.c:3390 memcg_slab_pre_alloc_hook mm/slab.h:501 [inline] slab_pre_alloc_hook+0x2e2/0x300 mm/slab.h:715 slab_alloc_node mm/slub.c:3279 [inline] slab_alloc mm/slub.c:3367 [inline] __kmem_cache_alloc_lru mm/slub.c:3374 [inline] kmem_cache_alloc+0x56/0x2f0 mm/slub.c:3383 kmem_cache_zalloc include/linux/slab.h:689 [inline] __alloc_file+0x25/0x230 fs/file_table.c:138 alloc_empty_file+0x90/0x180 fs/file_table.c:187 alloc_file+0x5b/0x5f0 fs/file_table.c:229 alloc_file_pseudo+0x180/0x200 fs/file_table.c:272 sock_alloc_file+0xb3/0x240 net/socket.c:467 sock_map_fd net/socket.c:491 [inline] __sys_socket+0x12d/0x190 net/socket.c:1679 __do_sys_socket net/socket.c:1684 [inline] __se_sys_socket net/socket.c:1682 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1682 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f2072f9de99 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:00007f2073dec028 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 00007f2073225fa0 RCX: 00007f2072f9de99 RDX: 0000000000000000 RSI: 0000000000000005 RDI: 000000000000000a RBP: 00007f2073033eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2073226038 R14: 00007f2073225fa0 R15: 00007fffe597a8d8