Re: Recent current panic

From: Guido Falsi <mad_at_madpilot.net>
Date: Wed, 08 Jul 2026 06:50:23 UTC
On 7/8/26 05:18, Kyle Evans wrote:
> On 7/7/26 14:36, Guido Falsi wrote:
>> On 7/7/26 20:40, Kyle Evans wrote:
>>> On 7/7/26 12:23, Guido Falsi wrote:
>>>> Hi!
>>>>
>>>> I'm experiencing a fully reproducible panic on recent current. I'm 
>>>> not sure what is triggering it, looks ZFS related but I could be 
>>>> wrong. It started when I updated shortly after the latest ZFS import.
>>>>
>>>> I'm running 2de20c5c77cf8d5b2059054cff0e0c1fc124739d committed on  
>>>> Fri Jul 3 10:55:37 2026 -0800 (from the commit message timestamp).
>>>>
>>>> first just after booting I get this report on the console:
>>>>
>>>> EFI RT fault page fault
>>>>
>>>> EFI runtime trap 12: page fault while in kernel mode
>>>> cpuid = 5; apic id = 05
>>>> fault virtual address    = 0x0
>>>> fault code        = supervisor read data, page not present
>>>> instruction pointer    = 0x20:0xb8bc1c5f
>>>> stack pointer            = 0x28:0xfffffe0121ae6c20
>>>> frame pointer            = 0x28:0x1
>>>> processor eflags    = interrupt enabled, resume, IOPL = 0
>>>> current thread        = 0/100045 (kernel/thread taskq)
>>>> rdi: fffffe0121ae6ce0 rsi: fffff80002523cd0 rdx: 0000000000000000
>>>> rcx: 00000000b8bc31b8  r8: 00000000b8bc3448  r9: 0000000000000006
>>>> rax: 00000000b9254e70 rbx: fffffe0121ae6d98 rbp: 0000000000000001
>>>> r10: 0000000000000000 r11: 0000000000000006 r12: fffff800014df658
>>>> r13: 0000000000000000 r14: fffffe0121ae6e08 r15: fffffe0121ae6da8
>>>>
>>>>
>>>> The system works fine after this, except if I start building a 
>>>> nanobsd image with scripts that have worked fine till now. Then when 
>>>> it tries to install packages in the image jail system panics hard:
>>>>
>>>
>>> This is fine- we trap EFIRT page faults and defang them because 
>>> firmware does stupid things at times.  It could still be worth 
>>> investigating to make sure we're not doing anything out-of-spec, but 
>>> I somewhat suspect this is just harmless.
>>
>> The machine in question is mostly headless, I just noticed this by 
>> chance, so, while I know for sure it was not doing this a year ago, it 
>> could have come a littel while ago.
>>
>> Anyway I now am sure the two errors are unrelated.
>>
>>>
>>>> Fatal trap 12: page fault while in kernel mode
>>>> cpuid = 1; apic id = 01
>>>> fault virtual address    = 0x180
>>>> fault code        = supervisor read data, page not present
>>>> instruction pointer    = 0x20:0xffffffff807a74e5
>>>> stack pointer            = 0x28:0xfffffe016f8ef9e0
>>>> frame pointer            = 0x28:0xfffffe016f8efd70
>>>> processor eflags    = interrupt enabled, resume, IOPL = 0
>>>> current thread        = 15751/101480 (sh/sh)
>>>> rdi: fffffe016369e984 rsi: fffff80035ad3000 rdx: 0000000000000000
>>>> rcx: 0000000000000000  r8: 0000000000006873  r9: 00000000ffffff01
>>>> rax: 0000000000000000 rbx: fffffe016369e984 rbp: fffffe016f8efd70
>>>> r10: 0000000000000001 r11: 0000000000000001 r12: fffffe016369e5a0
>>>> r13: 0000000000000000 r14: 0000000000000000 r15: 0000000000000000
>>>> panic: page fault
>>>> cpuid = 1
>>>> time = 1783444123
>>>> KDB: stack backtrace:
>>>> db_trace_self_wrapper() at db_trace_self_wrapper+0x36/frame 
>>>> 0xfffffe016f8ef720
>>>> vpanic() at vpanic+0x149/frame 0xfffffe016f8ef850
>>>> panic() at panic+0x43/frame 0xfffffe016f8ef8b0
>>>> trap_pfault() at trap_pfault+0x3a8/frame 0xfffffe016f8ef910
>>>> calltrap() at calltrap+0x8/frame 0xfffffe016f8ef910
>>>> --- trap 0xc, rip = 0xffffffff807a74e5, rsp = 0xfffffe016f8ef9e0, 
>>>> rbp = 0xfffffe016f8efd70 ---
>>>> kern_execve() at kern_execve+0x17f5/frame 0xfffffe016f8efd70
>>>> sys_execve() at sys_execve+0xc2/frame 0xfffffe016f8efe00
>>>> amd64_syscall() at amd64_syscall+0x133/frame 0xfffffe016f8eff30
>>>> fast_syscall_common() at fast_syscall_common+0xf8/frame 
>>>> 0xfffffe016f8eff30
>>>> --- syscall (59, FreeBSD ELF64, execve), rip = 0x605cefca, rsp = 
>>>> 0x881310ee8, rbp = 0x881311360 ---
>>>> KDB: enter: panic
>>>>
>>>>
>>>> Anyone can help I can trigger this easily. If someone could give me 
>>>> some steps to perform in the debugger to extract more information I 
>>>> can do that.
>>>>
>>>
>>> This looks remarkably what I have a fix for here: https:// 
>>> reviews.freebsd.org/D58063
>>>
>>> If nanobsd is trying to use qemu-user-static / imgact_binmisc, this 
>>> could easily explain it.  I expect to have a minute to land this here 
>>> within the next 6 hours or so.
>>>
>>
>> Yes, I forgot to mention in the report the NanoBSD images are for 
>> raspberry, so yes, I'm using qemu-user-static.
>>
>> A quick recompile with your patch fixed this issue and now I can 
>> compile images successfully.
>>
>> Thanks a lot, I can followup with a report to your review if needed.
>>
> Thanks for confirming- pushed in https://cgit.freebsd.org/src/commit/? 
> id=f5329a0d14712ae, slightly
> tweaked but not in a way that will affect the outcome.
> 
> Thanks,

Thanks a lot for your support!

-- 
Guido Falsi <mad@madpilot.net>