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Date: Wed, 30 Aug 2017 13:28:28 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Prakash Gupta <guptap@codeaurora.org>
Cc: mhocko@suse.com, vbabka@suse.cz, will.deacon@arm.com,
        catalin.marinas@arm.com, iamjoonsoo.kim@lge.com,
        rmk+kernel@arm.linux.org.uk, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH 1/2] arm64: stacktrace: avoid listing stacktrace
 functions in stacktrace
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On Wed, 30 Aug 2017 13:02:22 +0530 Prakash Gupta <guptap@codeaurora.org> wrote:

> The stacktraces always begin as follows:
> 
>  [<c00117b4>] save_stack_trace_tsk+0x0/0x98
>  [<c0011870>] save_stack_trace+0x24/0x28
>  ...
> 
> This is because the stack trace code includes the stack frames for itself.
> This is incorrect behaviour, and also leads to "skip" doing the wrong thing
> (which is the number of stack frames to avoid recording.)
> 
> Perversely, it does the right thing when passed a non-current thread.  Fix
> this by ensuring that we have a known constant number of frames above the
> main stack trace function, and always skip these.
> 
> This was fixed for arch arm by Commit 3683f44c42e9 ("ARM: stacktrace: avoid
> listing stacktrace functions in stacktrace")

I can take this (with acks, please?)

3683f44c42e9 has a cc:stable but your patch does not.  Should it?

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Date: Wed, 30 Aug 2017 13:28:28 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] arm64: stacktrace: avoid listing stacktrace
 functions in stacktrace
Message-Id: <20170830132828.0bf9b9bc64f51362a64a6694@linux-foundation.org>
In-Reply-To: <1504078343-28754-1-git-send-email-guptap@codeaurora.org>
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To: Prakash Gupta <guptap@codeaurora.org>
Cc: mhocko@suse.com, vbabka@suse.cz, will.deacon@arm.com, catalin.marinas@arm.com, iamjoonsoo.kim@lge.com, rmk+kernel@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-mm@kvack.org

On Wed, 30 Aug 2017 13:02:22 +0530 Prakash Gupta <guptap@codeaurora.org> wrote:

> The stacktraces always begin as follows:
> 
>  [<c00117b4>] save_stack_trace_tsk+0x0/0x98
>  [<c0011870>] save_stack_trace+0x24/0x28
>  ...
> 
> This is because the stack trace code includes the stack frames for itself.
> This is incorrect behaviour, and also leads to "skip" doing the wrong thing
> (which is the number of stack frames to avoid recording.)
> 
> Perversely, it does the right thing when passed a non-current thread.  Fix
> this by ensuring that we have a known constant number of frames above the
> main stack trace function, and always skip these.
> 
> This was fixed for arch arm by Commit 3683f44c42e9 ("ARM: stacktrace: avoid
> listing stacktrace functions in stacktrace")

I can take this (with acks, please?)

3683f44c42e9 has a cc:stable but your patch does not.  Should it?

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