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From: Waiman Long <llong@redhat.com>
To: Randy Dunlap <rdunlap@infradead.org>,
	Waiman Long <llong@redhat.com>, Ingo Molnar <mingo@kernel.org>
Cc: linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>,
	linux-xtensa@linux-xtensa.org,
	Johannes Berg <johannes@sipsolutions.net>,
	Jeff Dike <jdike@addtoit.com>,
	Richard Weinberger <richard@nod.at>,
	Anton Ivanov <anton.ivanov@cambridgegreys.com>,
	linux-um@lists.infradead.org
Subject: Re: [PATCH] LOCKDEP: use depends on LOCKDEP_SUPPORT instead of $ARCH list
Date: Mon, 24 May 2021 20:05:51 -0400	[thread overview]
Message-ID: <3a0fb04c-c640-25db-7e7a-fbdd3b4defb5@redhat.com> (raw)
In-Reply-To: <09243238-94ba-caca-441e-3fdac0154822@infradead.org>

On 5/24/21 5:41 PM, Randy Dunlap wrote:
> On 5/24/21 2:31 PM, Randy Dunlap wrote:
>> On 5/24/21 2:04 PM, Waiman Long wrote:
>>
>>> Is it possible to just get rid of the 2nd depends-on statement?
>>>
>>> The 2nd depends-on line was introduced by commit 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTER"):
>> and I should have looked at that history too. Thanks.
>>
>> Yes, I agree, we can just delete that line...
>>
>> I'll send a v2 and copy the author of commit 7d37cb2c912d as well.
> Hm, as I review that commit, I have to wonder if the previous 'select'
> was correct (if we disregard the Kconfig warning).  If so, then
> FRAME_POINTER is still wanted/needed for some arch-es.
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 2779c29d9981..417c3d3e521b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1363,7 +1363,7 @@ config LOCKDEP
>          bool
>          depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
>          select STACKTRACE
> -       select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 <<<<<<<<<<<
>
AFAICS, enabling FRAME_POINTER is a debugging aid as it enable more 
precise stacktrace. However, not all archs want to enable FRAME_POINTER 
because of LOCKDEP. Now you are just letting users decide if they want 
FRAME_POINTER or not. Maybe you can modify the help text to mention that.

Cheers,
Longman


  reply	other threads:[~2021-05-25  0:06 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-17  3:44 [PATCH] LOCKDEP: use depends on LOCKDEP_SUPPORT instead of $ARCH list Randy Dunlap
2021-05-17  7:11 ` Ingo Molnar
2021-05-17 14:02   ` Waiman Long
2021-05-23  3:12     ` Randy Dunlap
2021-05-24 19:47     ` Randy Dunlap
2021-05-24 21:04       ` Waiman Long
2021-05-24 21:31         ` Randy Dunlap
2021-05-24 21:41           ` Randy Dunlap
2021-05-25  0:05             ` Waiman Long [this message]
2021-05-25  4:18               ` Randy Dunlap
2021-05-25 14:15                 ` Waiman Long
2021-05-23  3:09   ` Randy Dunlap

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