rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 0, t=10502 jiffies, g=12677, q=742 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294959947-4294949445), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 10502 jiffies! g12677 f0x2 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:26728 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x14e2/0x4580 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6027 Comm: syz.1.27 Not tainted 6.6.99-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:deref_stack_reg+0x1db/0x240 arch/x86/kernel/unwind_orc.c:406
Code: 00 fc ff df 48 89 ef e8 63 08 00 00 49 89 c6 48 8b 5c 24 20 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 b5 0b a2 00 <4c> 89 33 b0 01 eb 0e e8 79 c5 4a 00 eb 05 e8 72 c5 4a 00 31 c0 48
RSP: 0018:ffffc9000380f678 EFLAGS: 00000046
RAX: 1ffff92000701efd RBX: ffffc9000380f7e8 RCX: ffff888028dc9e00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffc9000380fc40
RBP: ffffc9000380fc40 R08: ffff888028dc9e00 R09: 0000000000000003
R10: 0000000000000004 R11: 0000000000000000 R12: ffffc90003810000
R13: 1ffff92000701ef7 R14: ffff888028dca710 R15: dffffc0000000000
FS:  00007f20970dc6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000003102a000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 unwind_next_frame+0x1789/0x2970 arch/x86/kernel/unwind_orc.c:648
 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_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1806 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
 slab_free mm/slub.c:3816 [inline]
 kmem_cache_free+0xf8/0x280 mm/slub.c:3838
 __sigqueue_free kernel/signal.c:461 [inline]
 collect_signal kernel/signal.c:604 [inline]
 __dequeue_signal+0x52b/0x680 kernel/signal.c:626
 dequeue_signal+0xe9/0x4b0 kernel/signal.c:649
 get_signal+0x551/0x1400 kernel/signal.c:2782
 arch_do_signal_or_restart+0x96/0x780 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f209618e9a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f20970dc0e8 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 00007f20963b5fa8 RCX: 00007f209618e9a9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f20963b5fac
RBP: 00007f20963b5fa0 R08: 0000000000745d1e R09: 0000000000000000
R10: 0000000000000005 R11: 0000000000000246 R12: 00007f20963b5fac
R13: 0000000000000000 R14: 00007ffd545e3d50 R15: 00007ffd545e3e38
 </TASK>