linux-kernel - Re: stack frame unwindind KASAN errors

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMVG2ssW7_5ZdT1qdt2AB0vuNde7CgJ2ZkGn4U7LeY9gobNfjg@mail.gmail.com>
Date:   Tue, 7 Mar 2017 10:04:11 +0800
From:   Daniel J Blueman <daniel@...ra.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     Linux Kernel <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>
Subject: Re: stack frame unwindind KASAN errors

On 7 March 2017 at 00:40, Josh Poimboeuf <jpoimboe@...hat.com> wrote:
> On Mon, Mar 06, 2017 at 02:52:01PM +0800, Daniel J Blueman wrote:
>> Thanks Josh!
>>
>> With this patch, the KASAN warning still occurs, but at
>> unwind_get_return_address+0x1d3/0x130 instead; the rest of the trace
>> is identical.
>>
>> (gdb) list *(unwind_get_return_address+0x1d3)
>> 0xffffffff8112bca3 is in unwind_get_return_address
>> (./include/linux/compiler.h:243).
>> 238    })
>> 239
>> 240    static __always_inline
>> 241    void __read_once_size(const volatile void *p, void *res, int size)
>> 242    {
>> 243        __READ_ONCE_SIZE;
>
> Looking deeper, I have an idea about what's going on:
>
>   https://quora.org/dmesg.txt
>
> Each of the warnings seems to show an interrupt happening during an EFI
> call.  I'm guessing EFI modified the frame pointer, at least
> temporarily, which confused the unwinder :-(
>
> Would it be possible for you to test again with 4.10?  It has some
> additional unwinder output which should hopefully confirm my suspicions.

Very good; I don't see the KASAN warnings with 4.10 in the same environment.

Thanks,
  Daniel
-- 
Daniel J Blueman