From: rusty@rustcorp.com.au (Rusty Russell)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol
Date: Fri, 25 Oct 2013 22:28:29 +1030 [thread overview]
Message-ID: <87sivp7eai.fsf@rustcorp.com.au> (raw)
In-Reply-To: <CACVXFVPXEUX9JQ2NZvL8=J34zbw2fn202QW2SQtpKjdQ+tv=vg@mail.gmail.com>
Ming Lei <tom.leiming@gmail.com> writes:
> On Fri, Oct 25, 2013 at 1:50 PM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>> Ming Lei <tom.leiming@gmail.com> writes:
>>> On Fri, Oct 25, 2013 at 7:08 AM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>>>>
>>>> Sorry, I was imprecise. I was referring to the kernel's kallsyms
>>>> tables produced by scripts/kallsyms.c. This patch left them in the
>>>> the kallsyms tables and filtered them out from /proc/kallsyms.
>>>
>>> Yes, but it isn't easy to do it by script/kallsyms.c , and IMO, it should
>>> be correct to hide them for user space but keep them in kallsyms table.
>>
>> So they'll appear in backtraces? And turn up randomly for other symbol
>> dereferences?
>>
>> I don't think you really want this!
>
> Basically these symbols are only used to generate code, and in
> kernel mode, CPU won't run into the corresponding addresses
> because the generate code is copied to other address during booting,
> so I understand they won't appear in backtraces.
An oops occurs when something went *wrong*. We look up all kinds of
stuff. Are you so sure that *none* of the callers will ever see these
strange symbols and produce a confusing result?
Cheers,
Rusty.
WARNING: multiple messages have this Message-ID (diff)
From: Rusty Russell <rusty@rustcorp.com.au>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Chen Gang <gang.chen@asianux.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol
Date: Fri, 25 Oct 2013 22:28:29 +1030 [thread overview]
Message-ID: <87sivp7eai.fsf@rustcorp.com.au> (raw)
In-Reply-To: <CACVXFVPXEUX9JQ2NZvL8=J34zbw2fn202QW2SQtpKjdQ+tv=vg@mail.gmail.com>
Ming Lei <tom.leiming@gmail.com> writes:
> On Fri, Oct 25, 2013 at 1:50 PM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>> Ming Lei <tom.leiming@gmail.com> writes:
>>> On Fri, Oct 25, 2013 at 7:08 AM, Rusty Russell <rusty@rustcorp.com.au> wrote:
>>>>
>>>> Sorry, I was imprecise. I was referring to the kernel's kallsyms
>>>> tables produced by scripts/kallsyms.c. This patch left them in the
>>>> the kallsyms tables and filtered them out from /proc/kallsyms.
>>>
>>> Yes, but it isn't easy to do it by script/kallsyms.c , and IMO, it should
>>> be correct to hide them for user space but keep them in kallsyms table.
>>
>> So they'll appear in backtraces? And turn up randomly for other symbol
>> dereferences?
>>
>> I don't think you really want this!
>
> Basically these symbols are only used to generate code, and in
> kernel mode, CPU won't run into the corresponding addresses
> because the generate code is copied to other address during booting,
> so I understand they won't appear in backtraces.
An oops occurs when something went *wrong*. We look up all kinds of
stuff. Are you so sure that *none* of the callers will ever see these
strange symbols and produce a confusing result?
Cheers,
Rusty.
next prev parent reply other threads:[~2013-10-25 11:58 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-23 3:18 [RFC PATCH] kernel/kallsyms.c: only show legal kernel symbol Ming Lei
2013-10-23 3:18 ` Ming Lei
2013-10-24 1:21 ` Rusty Russell
2013-10-24 1:21 ` Rusty Russell
2013-10-24 5:42 ` Ming Lei
2013-10-24 5:42 ` Ming Lei
2013-10-24 8:45 ` Russell King - ARM Linux
2013-10-24 8:45 ` Russell King - ARM Linux
2013-10-24 9:10 ` Ming Lei
2013-10-24 9:10 ` Ming Lei
2013-10-24 23:08 ` Rusty Russell
2013-10-24 23:08 ` Rusty Russell
2013-10-25 1:29 ` Ming Lei
2013-10-25 1:29 ` Ming Lei
2013-10-25 5:50 ` Rusty Russell
2013-10-25 5:50 ` Rusty Russell
2013-10-25 7:01 ` Ming Lei
2013-10-25 7:01 ` Ming Lei
2013-10-25 11:58 ` Rusty Russell [this message]
2013-10-25 11:58 ` Rusty Russell
2013-10-26 12:31 ` Ming Lei
2013-10-26 12:31 ` Ming Lei
2013-10-28 3:14 ` Rusty Russell
2013-10-28 3:14 ` Rusty Russell
2013-10-28 5:23 ` Ming Lei
2013-10-28 5:23 ` Ming Lei
2013-10-28 5:50 ` Rusty Russell
2013-10-28 5:50 ` Rusty Russell
2013-10-30 23:09 ` Russell King - ARM Linux
2013-10-30 23:09 ` Russell King - ARM Linux
2013-10-31 3:14 ` Rusty Russell
2013-10-31 3:14 ` Rusty Russell
2013-10-31 4:55 ` Ming Lei
2013-10-31 4:55 ` Ming Lei
2013-11-01 2:28 ` Rusty Russell
2013-11-01 2:28 ` Rusty Russell
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