From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f176.google.com (mail-ig0-f176.google.com [209.85.213.176]) by kanga.kvack.org (Postfix) with ESMTP id 4E6D96B0035 for ; Thu, 31 Jul 2014 03:02:41 -0400 (EDT) Received: by mail-ig0-f176.google.com with SMTP id hn18so8839459igb.3 for ; Thu, 31 Jul 2014 00:02:40 -0700 (PDT) Received: from mail-ig0-x229.google.com (mail-ig0-x229.google.com [2607:f8b0:4001:c05::229]) by mx.google.com with ESMTPS id ga7si38093761igd.49.2014.07.31.00.02.40 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 31 Jul 2014 00:02:40 -0700 (PDT) Received: by mail-ig0-f169.google.com with SMTP id r2so1063635igi.2 for ; Thu, 31 Jul 2014 00:02:40 -0700 (PDT) Date: Thu, 31 Jul 2014 00:02:38 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR In-Reply-To: <1406787871-2951-1-git-send-email-cpandya@codeaurora.org> Message-ID: References: <1406787871-2951-1-git-send-email-cpandya@codeaurora.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Chintan Pandya Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org On Thu, 31 Jul 2014, Chintan Pandya wrote: > __kmap_atomic_idx is per_cpu variable. Each CPU can > use KM_TYPE_NR entries from FIXMAP i.e. from 0 to > KM_TYPE_NR - 1. Allowing __kmap_atomic_idx to over- > shoot to KM_TYPE_NR can mess up with next CPU's 0th > entry which is a bug. Hence BUG_ON if > __kmap_atomic_idx >= KM_TYPE_NR. > This appears to be a completely different patch, not a v2. Why is this check only done for CONFIG_DEBUG_HIGHMEM? I think Andrew's comment earlier was referring to the changelog only and not the patch, which looked correct. > Signed-off-by: Chintan Pandya > --- > Changes: > > V1 --> V2 > > Not touching CONFIG_DEBUG_HIGHMEM. > > include/linux/highmem.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/linux/highmem.h b/include/linux/highmem.h > index 7fb31da..9286a46 100644 > --- a/include/linux/highmem.h > +++ b/include/linux/highmem.h > @@ -93,7 +93,7 @@ static inline int kmap_atomic_idx_push(void) > > #ifdef CONFIG_DEBUG_HIGHMEM > WARN_ON_ONCE(in_irq() && !irqs_disabled()); > - BUG_ON(idx > KM_TYPE_NR); > + BUG_ON(idx >= KM_TYPE_NR); > #endif > return idx; > } -- 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: email@kvack.org