[v6.1] INFO: rcu detected stall in kvm_vm_release

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8ce36b2849ef Linux 6.1.163
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1482effa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=3680421d1bb466b52e37
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/25d3bb1313db/disk-8ce36b28.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/53d3c77e16da/vmlinux-8ce36b28.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ca171a78e481/bzImage-8ce36b28.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+368042...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8309/1:b..l
(detected by 1, t=10502 jiffies, g=39493, q=369 ncpus=2)
task:syz.3.971 state:R running task stack:26224 pid:8309 ppid:4280 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
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:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:244 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x80 kernel/kcov.c:313
Code: 77 22 89 ff 89 f6 49 ff c0 4c 89 01 48 c7 44 11 08 03 00 00 00 48 89 7c 11 10 48 89 74 11 18 48 89 44 11 20 c3 90 48 8b 04 24 <65> 48 8b 15 24 f8 7f 7e 65 8b 0d 25 f8 7f 7e 81 e1 00 01 ff 00 74
RSP: 0018:ffffc900033577e8 EFLAGS: 00000246
RAX: ffffffff818f1487 RBX: 0000000000000000 RCX: ffff88801bfe1dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff215ea48
R10: dffffc0000000000 R11: fffffbfff215ea49 R12: 0000000000000132
R13: dffffc0000000000 R14: 00007fc7dbd9c629 R15: 0000000000000000
rcu_read_unlock include/linux/rcupdate.h:820 [inline]
is_bpf_text_address+0x1f7/0x2a0 kernel/bpf/core.c:737
kernel_text_address+0x9c/0xd0 kernel/extable.c:125
__kernel_text_address+0x9/0x30 kernel/extable.c:79
unwind_get_return_address+0x49/0x80 arch/x86/kernel/unwind_orc.c:323
arch_stack_walk+0xf2/0x140 arch/x86/kernel/stacktrace.c:26
stack_trace_save+0xa6/0xf0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:53
kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:237
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xb6/0x1f0 mm/slub.c:3700
kvm_destroy_vm_debugfs virt/kvm/kvm_main.c:1039 [inline]
kvm_destroy_vm virt/kvm/kvm_main.c:1305 [inline]
kvm_put_kvm+0x1de/0x1950 virt/kvm/kvm_main.c:1370
kvm_vm_release+0x42/0x50 virt/kvm/kvm_main.c:1393
__fput+0x22c/0x920 fs/file_table.c:320
task_work_run+0x1d0/0x260 kernel/task_work.c:203
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
exit_to_user_mode_prepare+0xee/0x180 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:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc7dbd9c629
RSP: 002b:00007ffcae14f658 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007fc7dc017da0 RCX: 00007fc7dbd9c629
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007fc7dc017da0 R08: 00007fc7dc016038 R09: 0000000000000000
R10: 00000000005f902c R11: 0000000000000246 R12: 000000000004fa36
R13: 00007fc7dc01609c R14: 000000000004f77f R15: 00007fc7dc016090
</TASK>
rcu: rcu_preempt kthread starved for 10491 jiffies! g39493 f0x0 RCU_GP_DOING_FQS(6) ->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:28080 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5245 [inline]
__schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696
RIP: 0010:rcu_gp_fqs kernel/rcu/tree.c:-1 [inline]
RIP: 0010:rcu_gp_fqs_loop+0x579/0x1340 kernel/rcu/tree.c:1728
Code: 01 00 00 00 48 0f 48 d8 b9 01 00 00 00 45 31 f6 0f b6 05 ee 77 45 0b 84 c0 0f 85 bb fb ff ff e9 b0 fb ff ff 8b 1d 1f 78 45 0b <48> 8b 44 24 18 80 3c 30 00 74 16 48 c7 c7 00 f2 80 8c e8 30 a3 65
RSP: 0018:ffffc90000157cc0 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: dffffc0000000000 RDI: 00000000ffffffff
RBP: ffffc90000157e10 R08: ffffffff8cb330db R09: 1ffffffff196661b
R10: dffffc0000000000 R11: fffffbfff196661c R12: 0000000000000000
R13: ffffffff8cb33080 R14: ffffc90000157d88 R15: 0000000000000000
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
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741


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