* BUG: spinlock bad magic in lock_timer_base
@ 2025-07-03 8:54 白烁冉
2025-07-03 9:56 ` Thomas Gleixner
0 siblings, 1 reply; 4+ messages in thread
From: 白烁冉 @ 2025-07-03 8:54 UTC (permalink / raw)
To: Anna-Maria Behnsen, Frederic Weisbecker, Thomas Gleixner
Cc: Kun Hu, Jiaji Qin, linux-kernel, syzkaller
Dear Maintainers,
When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (110th)was triggered.
HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
git tree: upstream
Output:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/report110.txt
Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/config.txt
C reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.c Syzlang
reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.txt Our reproducer uses mounts a constructed filesystem image.
The error occurs in the lock_timer_base (timer.c lines 1770-1790 or so). It happens cleanup_srcu_struct during the KVM VM shutdown process, and it is likely that the memory pointed to by the timer object has been freed. The timer_base pointer returned by the get_timer_base (tf) points to an invalid memory area (__init_begin+0x2a500)
We have reproduced this issue several times on 6.14 again.
If you fix this issue, please add the following tag to the commit:
Reported-by: Kun Hu <huk23@m.fudan.edu.cn>, Jiaji Qin <jjtan24@m.fudan.edu.cn>, Shuoran Bai <baishuoran@hrbeu.edu.cn>
BUG: spinlock bad magic on CPU#2, syz.6.399/18129
lock: __init_begin+0x2a500/0x41000, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 2 UID: 0 PID: 18129 Comm: syz.6.399 Not tainted 6.14.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x116/0x1b0
do_raw_spin_lock+0x22c/0x2e0
_raw_spin_lock_irqsave+0x45/0x60
lock_timer_base+0x125/0x1c0
__try_to_del_timer_sync+0x7f/0x160
__timer_delete_sync+0x120/0x1c0
cleanup_srcu_struct+0x122/0x5a0
kvm_put_kvm+0x7c9/0xa10
kvm_vcpu_release+0x4b/0x70
__fput+0x417/0xb60
__fput_sync+0xa6/0xc0
__x64_sys_close+0x8b/0x120
do_syscall_64+0xcf/0x250
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fafdad1ebdb
Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffde8c95b20 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007fafdad1ebdb
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007ffde8c95bf8 R08: 0000000000000000 R09: 00007fafda8015a6
R10: 0000000000000001 R11: 0000000000000293 R12: 00007fafdafa5fa0
R13: 000000000002f3ea R14: ffffffffffffffff R15: 00007fafdafa5fa0
</TASK>
thanks,
Kun Hu
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: BUG: spinlock bad magic in lock_timer_base
2025-07-03 8:54 BUG: spinlock bad magic in lock_timer_base 白烁冉
@ 2025-07-03 9:56 ` Thomas Gleixner
[not found] ` <35941c6b.12afe.197de6fa934.Coremail.baishuoran@hrbeu.edu.cn>
0 siblings, 1 reply; 4+ messages in thread
From: Thomas Gleixner @ 2025-07-03 9:56 UTC (permalink / raw)
To: 白烁冉, Anna-Maria Behnsen, Frederic Weisbecker
Cc: Kun Hu, Jiaji Qin, linux-kernel, syzkaller, kvm, Paolo Bonzini
On Thu, Jul 03 2025 at 16:54, 白烁冉 wrote:
> Dear Maintainers,
The timer maintainers are hardly the right group to ask. The timer code
is just the messenger :)
I've Cc'ed the KVM folks, as you correctly identified KVM already as the
probable source of the problem.
> When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (110th)was triggered.
6.14 is not really the latest kernel.
> HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
> git tree: upstream
> Output:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/report110.txt
> Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/config.txt
> C reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.c Syzlang
> reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.txt Our reproducer uses mounts a constructed filesystem image.
>
> The error occurs in the lock_timer_base (timer.c lines 1770-1790 or
> so). It happens cleanup_srcu_struct during the KVM VM shutdown
> process, and it is likely that the memory pointed to by the timer
> object has been freed. The timer_base pointer returned by the
> get_timer_base (tf) points to an invalid memory area
> (__init_begin+0x2a500)
If you enable DEBUG_OBJECTS_TIMERS and DEBUG_OBJECTS_FREE the kernel
should survive and provide some useful output.
> We have reproduced this issue several times on 6.14 again.
Does the probkem still exist on the latest upstream kernel release
candidate, i.e. v6.16-rc4?
Leaving the report context intact for kvm folks.
Thanks,
tglx
> If you fix this issue, please add the following tag to the commit:
> Reported-by: Kun Hu <huk23@m.fudan.edu.cn>, Jiaji Qin <jjtan24@m.fudan.edu.cn>, Shuoran Bai <baishuoran@hrbeu.edu.cn>
>
>
>
>
> BUG: spinlock bad magic on CPU#2, syz.6.399/18129
> lock: __init_begin+0x2a500/0x41000, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> CPU: 2 UID: 0 PID: 18129 Comm: syz.6.399 Not tainted 6.14.0 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> Call Trace:
> <TASK>
> dump_stack_lvl+0x116/0x1b0
> do_raw_spin_lock+0x22c/0x2e0
> _raw_spin_lock_irqsave+0x45/0x60
> lock_timer_base+0x125/0x1c0
> __try_to_del_timer_sync+0x7f/0x160
> __timer_delete_sync+0x120/0x1c0
> cleanup_srcu_struct+0x122/0x5a0
> kvm_put_kvm+0x7c9/0xa10
> kvm_vcpu_release+0x4b/0x70
> __fput+0x417/0xb60
> __fput_sync+0xa6/0xc0
> __x64_sys_close+0x8b/0x120
> do_syscall_64+0xcf/0x250
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fafdad1ebdb
> Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
> RSP: 002b:00007ffde8c95b20 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
> RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007fafdad1ebdb
> RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000000000005
> RBP: 00007ffde8c95bf8 R08: 0000000000000000 R09: 00007fafda8015a6
> R10: 0000000000000001 R11: 0000000000000293 R12: 00007fafdafa5fa0
> R13: 000000000002f3ea R14: ffffffffffffffff R15: 00007fafdafa5fa0
> </TASK>
^ permalink raw reply [flat|nested] 4+ messages in thread
* BUG: spinlock bad magic in lock_timer_base
@ 2025-07-03 8:45 白烁冉
0 siblings, 0 replies; 4+ messages in thread
From: 白烁冉 @ 2025-07-03 8:45 UTC (permalink / raw)
Cc: Kun Hu, Jiaji Qin, linux-kernel, syzkaller
Dear Maintainers,
When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (110th)was triggered.
HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
git tree: upstream
Output:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/report110.txt
Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/config.txt
C reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.c Syzlang
reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0702_6.14/BUG%3A%20spinlock%20bad%20magic%20in%20lock_timer_base/110repro.txt Our reproducer uses mounts a constructed filesystem image.
The error occurs in the lock_timer_base (timer.c lines 1770-1790 or so). It happens cleanup_srcu_struct during the KVM VM shutdown process, and it is likely that the memory pointed to by the timer object has been freed. The timer_base pointer returned by the get_timer_base (tf) points to an invalid memory area (__init_begin+0x2a500)
We have reproduced this issue several times on 6.14 again.
If you fix this issue, please add the following tag to the commit:
Reported-by: Kun Hu <huk23@m.fudan.edu.cn>, Jiaji Qin <jjtan24@m.fudan.edu.cn>, Shuoran Bai <baishuoran@hrbeu.edu.cn>
BUG: spinlock bad magic on CPU#2, syz.6.399/18129
lock: __init_begin+0x2a500/0x41000, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
CPU: 2 UID: 0 PID: 18129 Comm: syz.6.399 Not tainted 6.14.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x116/0x1b0
do_raw_spin_lock+0x22c/0x2e0
_raw_spin_lock_irqsave+0x45/0x60
lock_timer_base+0x125/0x1c0
__try_to_del_timer_sync+0x7f/0x160
__timer_delete_sync+0x120/0x1c0
cleanup_srcu_struct+0x122/0x5a0
kvm_put_kvm+0x7c9/0xa10
kvm_vcpu_release+0x4b/0x70
__fput+0x417/0xb60
__fput_sync+0xa6/0xc0
__x64_sys_close+0x8b/0x120
do_syscall_64+0xcf/0x250
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fafdad1ebdb
Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2f 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44
RSP: 002b:00007ffde8c95b20 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007fafdad1ebdb
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007ffde8c95bf8 R08: 0000000000000000 R09: 00007fafda8015a6
R10: 0000000000000001 R11: 0000000000000293 R12: 00007fafdafa5fa0
R13: 000000000002f3ea R14: ffffffffffffffff R15: 00007fafdafa5fa0
</TASK>
thanks,
Kun Hu
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-07-06 7:16 UTC | newest]
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2025-07-03 8:54 BUG: spinlock bad magic in lock_timer_base 白烁冉
2025-07-03 9:56 ` Thomas Gleixner
[not found] ` <35941c6b.12afe.197de6fa934.Coremail.baishuoran@hrbeu.edu.cn>
2025-07-06 7:16 ` Re: " 白烁冉
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2025-07-03 8:45 白烁冉
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