All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ingo Molnar <mingo@elte.hu>
To: Jack Steiner <steiner@sgi.com>
Cc: tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] - Fix stack overflow for large values of MAX_APICS
Date: Fri, 20 Jun 2008 12:39:21 +0200	[thread overview]
Message-ID: <20080620103921.GC32500@elte.hu> (raw)
In-Reply-To: <20080620025104.GA25571@sgi.com>


* Jack Steiner <steiner@sgi.com> wrote:

> physid_mask_of_physid() causes a huge stack (12k) to be created if the 
> number of APICS is large. Replace physid_mask_of_physid() with a new 
> function that does not create large stacks. This is a problem only on 
> large x86_64 systems.

this indeed fixes the crash i reported here:

   http://lkml.org/lkml/2008/6/19/98

so i've added both this and the MAXAPICS patch to tip/x86/uv, and will 
test it some more. Lets hope it goes all well this time :-)

btw., it would be nice to have an ftrace plugin that prints out the 
worst-case stack footprint and generates an assert if we overflow the 
stack. -rt's kernel/latency_trace.c used to have that feature. That way 
incidents like this would be detected on the spot by -tip's 
auto-testing. The code in question is in kernel/trace/ftrace.c (and 
other nearby code).

	Ingo

WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@elte.hu>
To: Jack Steiner <steiner@sgi.com>
Cc: tglx@linutronix.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] - Fix stack overflow for large values of MAX_APICS
Date: Fri, 20 Jun 2008 12:39:21 +0200	[thread overview]
Message-ID: <20080620103921.GC32500@elte.hu> (raw)
In-Reply-To: <20080620025104.GA25571@sgi.com>

* Jack Steiner <steiner@sgi.com> wrote:

> physid_mask_of_physid() causes a huge stack (12k) to be created if the 
> number of APICS is large. Replace physid_mask_of_physid() with a new 
> function that does not create large stacks. This is a problem only on 
> large x86_64 systems.

this indeed fixes the crash i reported here:

   http://lkml.org/lkml/2008/6/19/98

so i've added both this and the MAXAPICS patch to tip/x86/uv, and will 
test it some more. Lets hope it goes all well this time :-)

btw., it would be nice to have an ftrace plugin that prints out the 
worst-case stack footprint and generates an assert if we overflow the 
stack. -rt's kernel/latency_trace.c used to have that feature. That way 
incidents like this would be detected on the spot by -tip's 
auto-testing. The code in question is in kernel/trace/ftrace.c (and 
other nearby code).

	Ingo

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply	other threads:[~2008-06-20 10:39 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-20  2:51 [PATCH] - Fix stack overflow for large values of MAX_APICS Jack Steiner
2008-06-20  2:51 ` Jack Steiner
2008-06-20 10:27 ` Ingo Molnar
2008-06-20 10:27   ` Ingo Molnar
2008-06-20 10:39 ` Ingo Molnar [this message]
2008-06-20 10:39   ` Ingo Molnar
2008-06-24 10:24   ` [bug] " Ingo Molnar
2008-06-24 10:24     ` Ingo Molnar
2008-06-24 22:03     ` Jack Steiner
2008-06-24 22:03       ` Jack Steiner
2008-06-25 20:56     ` Jack Steiner
2008-06-25 20:56       ` Jack Steiner
2008-06-26 12:32       ` Ingo Molnar
2008-06-26 12:32         ` Ingo Molnar
2008-06-26 12:41         ` Jack Steiner
2008-06-26 12:41           ` Jack Steiner
2008-06-26 22:38           ` Paul E. McKenney
2008-06-26 22:38             ` Paul E. McKenney
2008-06-26 22:58             ` Jack Steiner
2008-06-26 22:58               ` Jack Steiner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20080620103921.GC32500@elte.hu \
    --to=mingo@elte.hu \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=steiner@sgi.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.