Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756412AbaGaGYo (ORCPT ); Thu, 31 Jul 2014 02:24:44 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:41393 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753460AbaGaGYn (ORCPT ); Thu, 31 Jul 2014 02:24:43 -0400 From: Chintan Pandya To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Chintan Pandya Subject: [PATCH v2] mm: BUG when __kmap_atomic_idx equals KM_TYPE_NR Date: Thu, 31 Jul 2014 11:54:31 +0530 Message-Id: <1406787871-2951-1-git-send-email-cpandya@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __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. 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; } -- Chintan Pandya QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- 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/