syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P12758/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=60689, q=144 ncpus=2)
task:syz.5.1793      state:R  running task     stack:25320 pid:12758 ppid:6139   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758
Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00
RSP: 0018:ffffc900041d77a0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 9840ae34cfd0ac00
RDX: 0000000000000000 RSI: ffffffff8aaace20 RDI: ffffffff8afc71c0
RBP: ffffc900041d78a8 R08: dffffc0000000000 R09: 1ffffffff21b4ca0
R10: dffffc0000000000 R11: fffffbfff21b4ca1 R12: 1ffff9200083af00
R13: ffffffff8cd2fe20 R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline]
 percpu_ref_put+0x35/0x180 include/linux/percpu-refcount.h:351
 css_put include/linux/cgroup_refcnt.h:79 [inline]
 obj_cgroup_charge_pages mm/memcontrol.c:3115 [inline]
 __memcg_kmem_charge_page+0x264/0x380 mm/memcontrol.c:3135
 memcg_kmem_charge_page include/linux/memcontrol.h:1775 [inline]
 memcg_charge_kernel_stack+0x1c0/0x500 kernel/fork.c:261
 alloc_thread_stack_node kernel/fork.c:295 [inline]
 dup_task_struct+0x15b/0x7c0 kernel/fork.c:1124
 copy_process+0x549/0x3d70 kernel/fork.c:2331
 kernel_clone+0x21b/0x840 kernel/fork.c:2914
 __do_sys_clone3 kernel/fork.c:3215 [inline]
 __se_sys_clone3+0x252/0x2c0 kernel/fork.c:3199
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f75f71c3609
RSP: 002b:00007fff16c86ef8 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3
RAX: ffffffffffffffda RBX: 00007f75f71459f0 RCX: 00007f75f71c3609
RDX: 00007f75f71459f0 RSI: 0000000000000058 RDI: 00007fff16c86f40
RBP: 00007f75f7f936c0 R08: 00007f75f7f936c0 R09: 00007fff16c87027
R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8
R13: 000000000000006e R14: 00007fff16c86f40 R15: 00007fff16c87028
 </TASK>
rcu: rcu_preempt kthread starved for 10528 jiffies! g60689 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:26728 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 12759 Comm: syz.5.1793 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:60 [inline]
RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:393 [inline]
RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
RIP: 0010:unwind_next_frame+0xf25/0x2970 arch/x86/kernel/unwind_orc.c:585
Code: e8 90 e9 4a 00 85 ed 0f 95 c0 4c 39 f3 0f 96 c1 20 c1 4d 39 f7 0f 97 c0 84 c1 0f 84 fd 01 00 00 49 8d 46 08 48 39 d8 0f 97 c1 <4c> 39 f8 0f 96 c0 84 c1 48 8b 6c 24 10 0f 84 ab 05 00 00 e8 a3 e5
RSP: 0018:ffffc90000007878 EFLAGS: 00000002
RAX: ffffc90000007eb0 RBX: ffffc90000000000 RCX: 0000000000010001
RDX: ffff888029343c00 RSI: 0000000000000002 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffff888029343c00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000010000 R12: 1ffff92000000f2a
R13: 1ffff92000000f2b R14: ffffc90000007ea8 R15: ffffc90000008000
FS:  00007f75f7ff66c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffffb71f80 CR3: 000000005b9be000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 slab_alloc mm/slub.c:3503 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3510 [inline]
 kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3519
 __sigqueue_alloc+0x40c/0x520 kernel/signal.c:438
 __send_signal_locked+0x22f/0xe00 kernel/signal.c:1130
 do_send_sig_info kernel/signal.c:1312 [inline]
 group_send_sig_info+0x1fa/0x260 kernel/signal.c:1462
 do_bpf_send_signal+0x7f/0x190 kernel/trace/bpf_trace.c:836
 irq_work_single+0xd5/0x230 kernel/irq_work.c:221
 irq_work_run_list kernel/irq_work.c:252 [inline]
 irq_work_run+0x156/0x2e0 kernel/irq_work.c:261
 __sysvec_irq_work+0x98/0x380 arch/x86/kernel/irq_work.c:22
 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
 sysvec_irq_work+0x9c/0xc0 arch/x86/kernel/irq_work.c:17
 </IRQ>
 <TASK>
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline]
RIP: 0010:native_apic_msr_write+0x39/0x50 arch/x86/include/asm/apic.h:196
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 f3 0f 1e fa 89 f6 31 d2 e9 e7 e7 18 03 0f 1f 80 00 00 00
RSP: 0018:ffffc900047bfcd8 EFLAGS: 00000246
RAX: 00000000000000f6 RBX: 0000000000000200 RCX: 000000000000083f
RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f
RBP: 0000000000000000 R08: ffffc900047bfc47 R09: 1ffff920008f7f88
R10: dffffc0000000000 R11: fffff520008f7f89 R12: ffff8880b8e35001
R13: dffffc0000000000 R14: ffff8880b8e35050 R15: 0000000000000020
 __apic_send_IPI_self arch/x86/include/asm/apic.h:454 [inline]
 arch_irq_work_raise+0x68/0x70 arch/x86/kernel/irq_work.c:31
 irq_work_queue+0x99/0x140 kernel/irq_work.c:124
 bpf_send_signal_common+0x2b6/0x420 kernel/trace/bpf_trace.c:875
 ____bpf_send_signal kernel/trace/bpf_trace.c:884 [inline]
 bpf_send_signal+0x19/0x20 kernel/trace/bpf_trace.c:882
 bpf_prog_7ba5217f62dcd359+0x40/0x44
 bpf_dispatcher_nop_func include/linux/bpf.h:1223 [inline]
 __bpf_prog_run include/linux/filter.h:612 [inline]
 bpf_prog_run include/linux/filter.h:619 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2322 [inline]
 bpf_trace_run2+0x1d1/0x3c0 kernel/trace/bpf_trace.c:2361
 trace_sys_enter+0x69/0x80 include/trace/events/syscalls.h:18
 syscall_trace_enter+0xf0/0x150 kernel/entry/common.c:81
 do_syscall_64+0x28/0xb0 arch/x86/entry/common.c:77
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f75f712af79
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007f75f7ff5b40 EFLAGS: 00000246 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 00007f75f73e5fa8 RCX: 00007f75f712af79
RDX: 00007f75f7ff5b40 RSI: 00007f75f7ff5c70 RDI: 0000000000000011
RBP: 00007f75f73e5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f75f73e6038 R14: 00007fff16c86f40 R15: 00007fff16c87028
 </TASK>