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From: Andi Kleen <ak@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Zwane Mwaikambo <zwane@fsmlabs.com>,
	linux-kernel@vger.kernel.org, ak@suse.de, wli@holomorphy.com,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] remove LOCK_SECTION from x86_64 spin_lock asm
Date: Thu, 16 Sep 2004 08:13:59 +0200	[thread overview]
Message-ID: <20040916061359.GA12915@wotan.suse.de> (raw)
In-Reply-To: <20040915144523.0fec2070.akpm@osdl.org>

On Wed, Sep 15, 2004 at 02:45:23PM -0700, Andrew Morton wrote:
> Zwane Mwaikambo <zwane@fsmlabs.com> wrote:
> >
> > William spotted this stray bit, LOCK_SECTION isn't used anymore on x86_64. 
> 
> btw, Ingo and I were scratching heads over an x86_64 oops in curent -linus
> trees.
> 
> If you enable profiling and frame pointers, profile_pc() goes splat
> dereferencing the `regs' argument when it decides that the pc refers to a
> lock section.  Ingo said `regs' had a value of 0x2, iirc.  Consider this a
> bug report ;)

Known problem. Interrupts don't save regs->rbp, but the new profile_pc
that was introduced recently uses it.

One quick fix is to just use SAVE_ALL in the interrupt entry code,
but I don't like this because it will affect interrupt latency.

The real fix is to fix profile_pc to not reference it.

-Andi

  parent reply	other threads:[~2004-09-16  6:14 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-15 16:01 Zwane Mwaikambo
2004-09-15 21:45 ` Andrew Morton
2004-09-15 17:55   ` Zwane Mwaikambo
2004-09-15 21:47   ` Ingo Molnar
2004-09-16  6:13   ` Andi Kleen [this message]
2004-09-16  6:27     ` Ingo Molnar
2004-09-16  6:44       ` Andi Kleen
2004-09-16  6:51         ` Ingo Molnar
2004-09-16  6:53           ` Andi Kleen
2004-09-16  6:58             ` Ingo Molnar
2004-09-16  7:09               ` Andi Kleen
2004-09-16  7:19                 ` Ingo Molnar
2004-09-16  7:29                   ` Andi Kleen
2004-09-16  7:44                     ` Ingo Molnar
2004-09-16  7:53                       ` Andi Kleen
2004-09-16  9:01                       ` Andi Kleen
2004-09-16 12:44       ` Zwane Mwaikambo
2004-09-16 19:30         ` Ingo Molnar
2004-09-15 22:42 Andrew Chew

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