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From: "Will Deacon" <will.deacon@arm.com>
To: "'Anton Vorontsov'" <cbouatmailru@gmail.com>,
	<kgdb-bugreport@lists.sourceforge.net>
Cc: netdev@vger.kernel.org, Russell King <linux@arm.linux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	linux-arm-kernel@lists.infradead.org,
	Jason Wessel <jason.wessel@windriver.com>
Subject: RE: [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines
Date: Thu, 8 Jul 2010 09:48:56 +0100	[thread overview]
Message-ID: <27118.9785366461$1278579013@news.gmane.org> (raw)
In-Reply-To: <20100707171222.GA16448@oksana.dev.rtsoft.ru>

Hi Anton,

> It appears that KGDB can easily hang SMP ARM machines.

Yep. As pointed out at:

http://lkml.org/lkml/2010/4/8/214

Commit ae6bf53e broke kgdb on SMP systems because it incorrectly assumes
that atomic_{inc,dec} imply barriers. Until this is fixed, it will never
work reliably on ARM. Try reverting the patch [this doesn't completely
resolve the situation, but it might help].

> 1. I'm testing with I/D caches disabled. With enabled caches,
>    ARMv6K still locks-up. I'll test ARMv7 soon, and will try
>    to debug cache issues on ARMv6K.

This patch might help if you're using the ARM11MPCore:

http://lists.infradead.org/pipermail/linux-arm-kernel/2010-May/016567.html

Hope that helps,

Will

  parent reply	other threads:[~2010-07-08  8:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-07 17:12 [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 1/4] ARM: kgdb: Must poll for IPIs during busy-waiting Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 2/4] ARM: kgdb: Disable preemption before re-enabling interrupts Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 3/4] net: Implement napi_try_disable() Anton Vorontsov
2010-07-07 17:13 ` [PATCH RFC 4/4] kgdb: Quiesce IO back-end before rounding up secondary CPUs Anton Vorontsov
2010-07-07 17:54 ` [PATCH RFC 0/4] ARM/KGDB: Some fixes for SMP machines Anton Vorontsov
2010-07-08  8:48 ` Will Deacon [this message]
2010-07-08  8:48 ` Will Deacon

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