Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756404AbZCOJHB (ORCPT ); Sun, 15 Mar 2009 05:07:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752453AbZCOJGw (ORCPT ); Sun, 15 Mar 2009 05:06:52 -0400 Received: from smtp113.mail.mud.yahoo.com ([209.191.84.66]:34643 "HELO smtp113.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752553AbZCOJGv (ORCPT ); Sun, 15 Mar 2009 05:06:51 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=rOdXXJRw9EemywURmGfJD3H/GxiYrhON+LPyRPNRdSyG2DiNn/VeyXyjjwlTZ/oIlfOfsz4XUDCP1rDJso3Uj6kpyUagxYIoY1k11Up8tCr7k2VtSSSe9rzs2nCYCb4HO+j0QLq5K68QgZYEUvJjc3h8uVH7cSnp5ULmQiQQJro= ; X-YMail-OSG: i_EvRswVM1lQwItWhslDBmh13anMg5ejuOmasi1Q9JSnP6P.15nd_rjosLyRAMvthYtZRs2Q2rJIe2LIAUtdmV8B7X8HYZ53wV9BID7xXDuZtyonHbZT9kHJCTCAGHE8nxc.gvPTeEaw2ckgAYrBv1xAcVfu8g5fSD_64480PIjVBtjNJao4JObjUfau3HCj_ga2KQbXIP9QWHr0DAVIcBwVo0buVQ-- X-Yahoo-Newman-Property: ymail-3 From: Nick Piggin To: Ingo Molnar Subject: Re: SLOB lockup (was: Re: [tip:core/locking] lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB) Date: Sun, 15 Mar 2009 20:06:20 +1100 User-Agent: KMail/1.9.51 (KDE/4.0.4; ; ) Cc: linux-tip-commits@vger.kernel.org, Nick Piggin , Peter Zijlstra , Pekka Enberg , Matt Mackall , linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de References: <20090128135457.350751756@chello.nl> <20090315064818.GA1193@elte.hu> In-Reply-To: <20090315064818.GA1193@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200903152006.21160.nickpiggin@yahoo.com.au> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1626 Lines: 49 On Sunday 15 March 2009 17:48:18 Ingo Molnar wrote: > > Cc: Nick Piggin > > Cc: Peter Zijlstra > > LKML-Reference: <20090128135457.350751756@chello.nl> > > Signed-off-by: Ingo Molnar > > and with this fixed, and with SLOB now being tested in -tip, the > new lockdep assert attached below (followed by a real lockup) > pops up. > > Seems like a genuine SLOB bug, probably present upstream as > well. Hmmf. debugobjects calls back into the slab allocator from the page allocator. The following patch would improve SLOB, but I think it would be a good idea to avoid a dependency in that direction. Can debugobjects defer this freeing? --- mm/slob.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) Index: linux-2.6/mm/slob.c =================================================================== --- linux-2.6.orig/mm/slob.c +++ linux-2.6/mm/slob.c @@ -390,13 +390,14 @@ static void slob_free(void *block, int s spin_lock_irqsave(&slob_lock, flags); if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) { + spin_lock_irqrestore(&slob_lock, flags); /* Go directly to page allocator. Do not pass slob allocator */ if (slob_page_free(sp)) clear_slob_page_free(sp); clear_slob_page(sp); free_slob_page(sp); free_page((unsigned long)b); - goto out; + return; } if (!slob_page_free(sp)) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/