Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it

From	Andy Lutomirski <luto@amacapital.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it
Date	2016-05-29 18:50 +0200
Message-ID	<rEc4y-h4-31@gated-at.bofh.it> (permalink)
References	<rCtjb-Ur-9@gated-at.bofh.it> <rCtjc-Ur-17@gated-at.bofh.it> <rCFkl-qt-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, May 25, 2016 at 4:39 AM, Borislav Petkov <bp@alien8.de> wrote:
> On Tue, May 24, 2016 at 03:48:41PM -0700, Andy Lutomirski wrote:
>> This will help debug OOPSes related to USER_DS vs KERNEL_DS.
>>
>> Signed-off-by: Andy Lutomirski <luto@kernel.org>
>> ---
>>  arch/x86/kernel/dumpstack_32.c | 4 ++++
>>  arch/x86/kernel/dumpstack_64.c | 5 +++++
>>  2 files changed, 9 insertions(+)
>>
>> diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
>> index 464ffd69b92e..5dbb08fd8291 100644
>> --- a/arch/x86/kernel/dumpstack_32.c
>> +++ b/arch/x86/kernel/dumpstack_32.c
>> @@ -124,8 +124,12 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
>>  void show_regs(struct pt_regs *regs)
>>  {
>>       int i;
>> +     struct thread_info *ti = current_thread_info();
>>
>>       show_regs_print_info(KERN_EMERG);
>> +     if (ti->addr_limit.seg != TASK_SIZE_MAX)
>> +             printk(KERN_DEFAULT "task.addr_limit: 0x%lx\n",
>> +                    ti->addr_limit.seg);
>
> And, of course, that printk should be part of the printk in
> show_regs_print_info() and not duplicated here and in dumpstack_64.c

Easier said than done.  struct thread_info doesn't have addr_limit on
sensible architectures (e.g. sparc), and I'd rather not stick a bunch
of ifdefs in generic code.

--Andy

Thread

[PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Andy Lutomirski <luto@kernel.org> - 2016-05-25 00:50 +0200
  Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display  it Borislav Petkov <bp@alien8.de> - 2016-05-25 13:40 +0200
    Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Andy Lutomirski <luto@amacapital.net> - 2016-05-29 18:50 +0200
      Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Boris Petkov <bp@alien8.de> - 2016-05-29 20:50 +0200
        Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Andy Lutomirski <luto@amacapital.net> - 2016-05-29 21:10 +0200
          Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display  it Borislav Petkov <bp@alien8.de> - 2016-05-30 09:50 +0200
  Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display  it Borislav Petkov <bp@alien8.de> - 2016-05-25 13:40 +0200
    Re: [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Andy Lutomirski <luto@amacapital.net> - 2016-05-29 18:50 +0200

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