syzbot
WARNING in kvm_put_kvm (3)
Status:
upstream: reported syz repro on 2026/08/09 19:14
Subsystems:
kvm
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+d4faf7db59e11f6fd1ab@syzkaller.appspotmail.com
First crash: 34d, last: 6d02h
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Last patch testing requests (3)
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Cause bisection attempts (1)
| Created |
Duration |
User |
Patch |
Repo |
Result |
| 2026/08/10 14:08 |
0m
|
bisect
|
|
linux-next |
error
|
Sample crash report:
------------[ 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.1.2967/14762
Modules linked in:
CPU: 0 UID: 0 PID: 14762 Comm: syz.1.2967 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: c7 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:ffffc90005cbfc10 EFLAGS: 00010202
RAX: 1ffffd1ffff87ffd RBX: 0000607edaf66f00 RCX: dffffc0000000000
RDX: 0000000000000001 RSI: ffffffff8e4744cc RDI: 00000000ffffffff
RBP: ffffe8ffffc3ff00 R08: ffffffff907a167f R09: 1ffffffff20f42cf
R10: dffffc0000000000 R11: fffffbfff20f42d0 R12: ffff88802c219800
R13: 0000000000000000 R14: ffffe8ffffc3ffe8 R15: 1ffffffff1ce8dde
FS: 0000000000000000(0000) GS:ffff888124cd9000(0063) knlGS:0000000057596480
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002d863fff CR3: 00000000796c4000 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: 0023:0xf7f260ec
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:00000000f750fb1c 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
* Struck through repros no longer work on HEAD.