From: syzbot <syzbot+d4faf7db59e11f6fd1ab@syzkaller.appspotmail.com>
To: frederic@kernel.org, jiangshanlai@gmail.com,
josh@joshtriplett.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com,
paulmck@kernel.org, pbonzini@redhat.com, qiang.zhang@linux.dev,
rcu@vger.kernel.org, rostedt@goodmis.org, seanjc@google.com,
shpark061104@gmail.com, syzkaller-bugs@googlegroups.com,
work@onurozkan.dev
Subject: Re: [syzbot] [kvm?] WARNING in kvm_put_kvm (3)
Date: Mon, 14 Sep 2026 00:03:30 -0700 [thread overview]
Message-ID: <6aa79c42.4c28b7d0.c1bba.0014.GAE@google.com> (raw)
In-Reply-To: <6a78d191.b50370da.49fe0.0042.GAE@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: 50d05c7c76c9 Merge tag 'landlock-7.3-rc3' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1779e925580000
kernel config: https://syzkaller.appspot.com/x/.config?x=5e4e3a0e188a497e
dashboard link: https://syzkaller.appspot.com/bug?extid=d4faf7db59e11f6fd1ab
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14ef08c9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f9e925580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/daf497619736/disk-50d05c7c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/748fbd82f647/vmlinux-50d05c7c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e61c59099d07/bzImage-50d05c7c.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d4faf7db59e11f6fd1ab@syzkaller.appspotmail.com
------------[ cut here ]------------
timer_delete_sync(&sdp->delay_work) && rcu_segcblist_n_cbs(&sdp->srcu_cblist)
WARNING: kernel/rcu/srcutree.c:707 at cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706, CPU#0: syz.0.4746/16077
Modules linked in:
CPU: 0 UID: 0 PID: 16077 Comm: syz.0.4746 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:cleanup_srcu_struct+0x3d6/0x8b0 kernel/rcu/srcutree.c:706
Code: fd 8b 00 48 83 7d 00 00 4c 8b 74 24 10 0f 85 dd 03 00 00 41 ff c5 41 83 e5 0f 41 83 fd 07 0f 86 e2 fe ff ff e9 ab 00 00 00 90 <0f> 0b 90 4c 8d b5 00 02 00 00 4c 89 f3 48 c1 eb 03 48 b8 00 00 00
RSP: 0018:ffffc90002e2fc10 EFLAGS: 00010206
RAX: 1ffffd1ffff8ff4d RBX: 0000607edafad980 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8e475f59 RDI: 00000000ffffffff
RBP: ffffe8ffffc7f980 R08: ffffffff907a2b7f R09: 1ffffffff20f456f
R10: dffffc0000000000 R11: fffffbfff20f4570 R12: ffff88802b081000
R13: 0000000000000000 R14: ffffe8ffffc7fa68 R15: 1ffffffff1ce91de
FS: 0000000000000000(0000) GS:ffff888124cd2000(0063) knlGS:0000000057310480
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000073e86000 CR4: 00000000003526f0
Call Trace:
<TASK>
kvm_destroy_vm virt/kvm/kvm_main.c:1303 [inline]
kvm_put_kvm+0x9cb/0xb50 virt/kvm/kvm_main.c:1332
kvm_vm_release+0x43/0x50 virt/kvm/kvm_main.c:1355
__fput+0x418/0xa50 fs/file_table.c:512
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline]
__do_fast_syscall_32+0x437/0x6a0 arch/x86/entry/syscall_32.c:294
do_fast_syscall_32+0x33/0x70 arch/x86/entry/syscall_32.c:316
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f470ec
Code: 90 85 d2 74 0a 89 ce 81 e6 ff 0f 00 00 89 32 85 c0 74 05 c1 e9 0c 89 08 31 c0 5e 5d c3 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 58 b8
RSP: 002b:00000000ffa0002c EFLAGS: 00000206 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 000000000000001e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
</TASK>
----------------
Code disassembly (best guess):
0: 90 nop
1: 85 d2 test %edx,%edx
3: 74 0a je 0xf
5: 89 ce mov %ecx,%esi
7: 81 e6 ff 0f 00 00 and $0xfff,%esi
d: 89 32 mov %esi,(%rdx)
f: 85 c0 test %eax,%eax
11: 74 05 je 0x18
13: c1 e9 0c shr $0xc,%ecx
16: 89 08 mov %ecx,(%rax)
18: 31 c0 xor %eax,%eax
1a: 5e pop %rsi
1b: 5d pop %rbp
1c: c3 ret
1d: 90 nop
1e: 0f 1f 00 nopl (%rax)
21: 51 push %rcx
22: 52 push %rdx
23: 55 push %rbp
24: 89 e5 mov %esp,%ebp
26: 0f 34 sysenter
28: cd 80 int $0x80
* 2a: 5d pop %rbp <-- trapping instruction
2b: 5a pop %rdx
2c: 59 pop %rcx
2d: c3 ret
2e: 90 nop
2f: 90 nop
30: 90 nop
31: 90 nop
32: 90 nop
33: 90 nop
34: 90 nop
35: 90 nop
36: 90 nop
37: 90 nop
38: 90 nop
39: 90 nop
3a: 90 nop
3b: 90 nop
3c: 90 nop
3d: 90 nop
3e: 58 pop %rax
3f: b8 .byte 0xb8
---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
next prev parent reply other threads:[~2026-09-14 7:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-09 19:14 syzbot
2026-08-23 9:33 ` Forwarded: test for d4faf7db59e11f6fd1ab syzbot
2026-08-23 10:10 ` Forwarded: test patch " syzbot
2026-08-24 3:57 ` Forwarded: test " syzbot
2026-09-14 7:03 ` syzbot [this message]
2026-09-14 11:55 ` [syzbot] [kvm?] WARNING in kvm_put_kvm (3) Zqiang
[not found] <CAEv4s6fQGiegVED5qRu8reFNwFqpY_aDM_LSWic+aa8RYk2m6g@mail.gmail.com>
2026-08-23 10:09 ` syzbot
[not found] <CAEv4s6dfmd+J0-yjShd_cQDJLHJFCDN9Bf=QbVmbwFkkx6vqCQ@mail.gmail.com>
2026-08-23 11:01 ` syzbot
[not found] <CAEv4s6cqTSfVRkzNBxefk=TciP94RQF6CFJc583h8hoonKeUSw@mail.gmail.com>
2026-08-24 5:37 ` syzbot
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