From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: -next March 3: Boot failure on x86 (Oops) Date: Fri, 05 Mar 2010 15:17:56 +0900 Message-ID: <4B90A214.70301@kernel.org> References: <20100303174603.5be197ba.sfr@canb.auug.org.au> <4B8E83D4.6090507@in.ibm.com> <4B8F0CD0.1040507@kernel.org> <4B8F43DD.10002@in.ibm.com> <4B909FC5.8020800@kernel.org> <4B90A031.8090306@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4B90A031.8090306@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: Sachin Sant Cc: linux-next@vger.kernel.org, LKML List-Id: linux-next.vger.kernel.org Hello, On 03/05/2010 03:09 PM, Tejun Heo wrote: > On 03/05/2010 03:08 PM, Tejun Heo wrote: >> Hmmm... this means that on one of the chunks, chunk->list.next was >> NULL (BTW, the disassembly is from unlinked object, right?). The main >> allocation code hasn't seen much change lately. The only changes are, >> >> 22b737f4c75197372d64afc6ed1bccd58c00e549 : just refactoring >> 833af8427be4b217b5bc522f61afdbd3f1d282c2 : possible but isn't very new > > Can you also please try reverting the above two commits? Sorry about all the fuss but I think this could be it. It looks like I forgot to update need_to_extend logic while adding simultaneous head/tail split for alignment, so the array might be overrun by one entry. Can you please try this one first? Thanks. diff --git a/mm/percpu.c b/mm/percpu.c index 768419d..f1ed9ea 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -373,11 +373,11 @@ static int pcpu_need_to_extend(struct pcpu_chunk *chunk) { int new_alloc; - if (chunk->map_alloc >= chunk->map_used + 2) + if (chunk->map_alloc >= chunk->map_used + 3) return 0; new_alloc = PCPU_DFL_MAP_ALLOC; - while (new_alloc < chunk->map_used + 2) + while (new_alloc < chunk->map_used + 3) new_alloc *= 2; return new_alloc; -- tejun