From: Florian Fainelli <f.fainelli@gmail.com>
To: Alexander Sverdlin <alexander.sverdlin@nokia.com>,
Qais Yousef <qais.yousef@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Russell King <linux@armlinux.org.uk>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH v7 2/2] ARM: ftrace: Add MODULE_PLTS support
Date: Wed, 10 Mar 2021 08:14:07 -0800 [thread overview]
Message-ID: <05608bc8-f44d-5f91-15ab-af00c59b53e6@gmail.com> (raw)
In-Reply-To: <3eecf51d-b189-9e8b-f19d-a49d0764aae5@nokia.com>
On 3/9/2021 11:23 PM, Alexander Sverdlin wrote:
> Hi!
>
> On 09/03/2021 18:42, Qais Yousef wrote:
>>>> I tried on 5.12-rc2 and 5.11 but couldn't reproduce the problem using your
>> I still can't reproduce on 5.12-rc2.
>>
>> I do have CONFIG_ARM_MODULE_PLTS=y. Do you need to do something else after
>> loading the module? I tried starting ftrace, but maybe there's a particular
>> combination required?
>
> You need to load a BIG module, so big that it has no place in the modules area
> any more and goes to vmalloc area.
You absolutely need a very big module maybe more than one. When I tested
this, I could use the two proprietary modules (*sigh*) that I needed to
exercise against and loading one but not the other was not enough to
make the second module loading spill into vmalloc space.
>
>>>> instructions on the other email. But most likely because I'm hitting another
>>>> problem that could be masking it. I'm not sure it is related or just randomly
>>>> happened to hit it.
>>>>
>>>> Did you see something similar?
>>> [...]
>>>
>>>> [ 0.000000] [<c1b01a38>] (ftrace_bug) from [<c046316c>] (ftrace_process_locs+0x2b0/0x518)
>>>> [ 0.000000] r7:c3817ac4 r6:c38040c0 r5:00000a3c r4:000134e4
>>>> [ 0.000000] [<c0462ebc>] (ftrace_process_locs) from [<c2b25240>] (ftrace_init+0xc8/0x174)
>>>> [ 0.000000] r10:c2ffa000 r9:c2be8a78 r8:c2c5d1fc r7:c2c0c208 r6:00000001 r5:c2d0908c
>>>> [ 0.000000] r4:c362f518
>>>> [ 0.000000] [<c2b25178>] (ftrace_init) from [<c2b00e14>] (start_kernel+0x2f4/0x5b8)
>>>> [ 0.000000] r9:c2be8a78 r8:dbfffec0 r7:00000000 r6:c36385cc r5:c2d08f00 r4:c2ffa000
>>>> [ 0.000000] [<c2b00b20>] (start_kernel) from [<00000000>] (0x0)
>>> This means, FTRACE has more problems with your kernel/compiler/platform, I've addressed similar issue
>>> in the past, but my patch should be long merged:
>>>
>>> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1817963.html
>>>
>>> Could it be the same problem as here:
>>> https://www.spinics.net/lists/arm-kernel/msg854022.html
>>>
>>> Seems that the size check deserves something line BUILD_BUG_ON() with FTRACE...
>> So I only see this when I convert all modules to be built-in
>>
>> sed -i 's/=m/=y/' .config
>>
>> FWIW, I see the problem with your patch applied too. Trying to dig more into
>> it..
>
> Then it's definitely the problem explained in the second link. If you have THUMB2 kernel, maybe
> you have to switch to ARM.
>
--
Florian
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next prev parent reply other threads:[~2021-03-10 16:15 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-27 11:09 [PATCH v7 0/2] ARM: Implement MODULE_PLT support in FTRACE Alexander A Sverdlin
2021-01-27 11:09 ` [PATCH v7 1/2] ARM: PLT: Move struct plt_entries definition to header Alexander A Sverdlin
2021-01-27 20:25 ` Florian Fainelli
2021-01-27 11:09 ` [PATCH v7 2/2] ARM: ftrace: Add MODULE_PLTS support Alexander A Sverdlin
2021-01-27 19:36 ` Florian Fainelli
2021-03-07 17:26 ` Qais Yousef
2021-03-08 7:58 ` Alexander Sverdlin
2021-03-09 17:42 ` Qais Yousef
2021-03-10 7:23 ` Alexander Sverdlin
2021-03-10 16:14 ` Florian Fainelli [this message]
2021-03-10 17:17 ` Alexander Sverdlin
2021-03-12 17:24 ` Qais Yousef
2021-03-12 18:35 ` Florian Fainelli
2021-03-14 22:02 ` Qais Yousef
2021-03-21 19:06 ` Qais Yousef
2021-03-22 15:01 ` Steven Rostedt
2021-03-22 16:32 ` Qais Yousef
2021-03-22 17:02 ` Alexander Sverdlin
2021-03-23 22:22 ` Qais Yousef
2021-03-24 3:37 ` Florian Fainelli
2021-03-24 16:10 ` Qais Yousef
2021-03-24 9:04 ` Alexander Sverdlin
2021-03-24 15:57 ` Qais Yousef
2021-03-24 16:33 ` Alexander Sverdlin
2021-03-24 16:46 ` Qais Yousef
2021-03-15 9:19 ` Alexander Sverdlin
2021-02-03 18:23 ` [PATCH v7 0/2] ARM: Implement MODULE_PLT support in FTRACE Florian Fainelli
2021-02-15 18:31 ` Ard Biesheuvel
2021-03-02 8:29 ` Linus Walleij
2021-03-02 10:00 ` Alexander Sverdlin
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