linux-kernel - Re: [PATCH] x86/unwind/orc: Do not skip the first frame unless explicitly asked for

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Message-ID: <20200304174749.iwoyf5gp4lkb22t5@treble>
Date:   Wed, 4 Mar 2020 11:47:49 -0600
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Miroslav Benes <mbenes@...e.cz>
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86/unwind/orc: Do not skip the first frame unless
 explicitly asked for

On Wed, Mar 04, 2020 at 01:32:59PM +0100, Miroslav Benes wrote:
> ORC unwinder can currently skip the first frame even if a user does not
> ask for it. If both regs and first_frame parameters of unwind_start()
> are set to NULL, state->sp and first_frame are later initialized to the
> same value for an inactive task. Given there is "less than or equal to"
> comparison used at the end of __unwind_start() for skipping stack frames,
> the first frame is always skipped in this case.
> 
> Drop the equal part of the comparison and make it equivalent to the
> frame pointer unwinder.
> 
> Signed-off-by: Miroslav Benes <mbenes@...e.cz>

Acked-by: Josh Poimboeuf <jpoimboe@...hat.com>

-- 
Josh