rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P10207/1:b..l
	(detected by 0, t=10503 jiffies, g=54677, q=156 ncpus=2)
task:syz.6.1344      state:R  running task     stack:26496 pid:10207 ppid:7812   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666
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 44 3d 00 00 00 00 00 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b
RSP: 0018:ffffc9000513fc80 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 9e7d513cc926b500
RDX: 0000000000000000 RSI: ffffffff8a8c15e0 RDI: ffffffff8adf1c20
RBP: ffffc9000513fd88 R08: dffffc0000000000 R09: fffffbfff215c449
R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: 0000000000000000
R13: 1ffff92000a27f9c R14: 0000000000000246 R15: dffffc0000000000
 rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 rcu_read_lock include/linux/rcupdate.h:791 [inline]
 mntput_no_expire+0xd3/0x850 fs/namespace.c:1208
 __do_sys_chdir fs/open.c:525 [inline]
 __se_sys_chdir+0x1bf/0x280 fs/open.c:508
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fb2cad8d677
RSP: 002b:00007fb2cbb0fe68 EFLAGS: 00000206 ORIG_RAX: 0000000000000050
RAX: ffffffffffffffda RBX: 00007fb2cbb0fef0 RCX: 00007fb2cad8d677
RDX: 0000000000000003 RSI: 0000200000000140 RDI: 0000200000000140
RBP: 0000200000000440 R08: 0000000000000000 R09: 0000000000200000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000200000000140
R13: 00007fb2cbb0feb0 R14: 0000000000000570 R15: 0000200000000200
 </TASK>
rcu: rcu_preempt kthread starved for 10525 jiffies! g54677 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:27552 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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: 10205 Comm: syz.4.1343 Not tainted 6.1.145-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:unwind_next_frame+0x6e2/0x20b0 arch/x86/kernel/unwind_orc.c:471
Code: 80 e1 07 38 c1 0f 8c 75 02 00 00 be 02 00 00 00 49 89 d6 4c 89 ff e8 bd f8 99 00 e9 3b 18 00 00 48 8b 44 24 50 42 80 3c 28 00 <4c> 8b 74 24 58 74 08 4c 89 f7 e8 df f7 99 00 49 8b 16 4d 8d 7c 24
RSP: 0018:ffffc9000515f5f0 EFLAGS: 00000046
RAX: 1ffff92000a2bee0 RBX: ffffc9000515f6c8 RCX: ffffffff8e2f33f4
RDX: ffffffff8e9f0a82 RSI: ffffffff8e2f33f0 RDI: 0000000000000001
RBP: ffffffff8e9f0a86 R08: 0000000000000009 R09: 0000000000000005
R10: fffff52000a2bee5 R11: 1ffff92000a2bee3 R12: ffffffff8e9f0a82
R13: dffffc0000000000 R14: ffffffff8e2f33f0 R15: 0000000000000005
FS:  00007f7be84906c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000077c40000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1724 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0xf7/0x290 mm/slub.c:3683
 __sigqueue_free kernel/signal.c:459 [inline]
 collect_signal kernel/signal.c:602 [inline]
 __dequeue_signal+0x4e9/0x610 kernel/signal.c:624
 dequeue_signal+0xe5/0x4b0 kernel/signal.c:647
 get_signal+0x547/0x1350 kernel/signal.c:2751
 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
 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:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f7be758e929
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:00007f7be84900e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007f7be77b5fa8 RCX: 00007f7be758e929
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f7be77b5fa8
RBP: 00007f7be77b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f7be77b5fac
R13: 0000000000000000 R14: 00007fffc20b1270 R15: 00007fffc20b1358
 </TASK>
vkms_vblank_simulate: vblank timer overrun