From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753289AbbICHzg (ORCPT ); Thu, 3 Sep 2015 03:55:36 -0400 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:39182 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753110AbbICHze (ORCPT ); Thu, 3 Sep 2015 03:55:34 -0400 X-Helo: d23dlp01.au.ibm.com X-MailFrom: aneesh.kumar@linux.vnet.ibm.com X-RcptTo: linux-kernel@vger.kernel.org From: "Aneesh Kumar K.V" To: akpm@linux-foundation.org, Andrey Ryabinin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" Subject: [PATCH 4/4] kasan: Prevent deadlock in kasan reporting Date: Thu, 3 Sep 2015 13:24:23 +0530 Message-Id: <1441266863-5435-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1441266863-5435-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1441266863-5435-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15090307-0025-0000-0000-00000213649A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We we end up calling kasan_report in real mode, our shadow mapping for even spinlock variable will show poisoned. This will result in us calling kasan_report_error with lock_report spin lock held. To prevent this disable kasan reporting when we are priting error w.r.t kasan. Signed-off-by: Aneesh Kumar K.V --- mm/kasan/report.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 440bda3a3ecd..8c409b1664c8 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -173,12 +173,10 @@ static void print_shadow_for_address(const void *addr) * function, because generic functions may try to * access kasan mapping for the passed address. */ - kasan_disable_current(); memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW); print_hex_dump(KERN_ERR, buffer, DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1, shadow_buf, SHADOW_BYTES_PER_ROW, 0); - kasan_enable_current(); if (row_is_guilty(shadow_row, shadow)) pr_err("%*c\n", @@ -195,6 +193,10 @@ void kasan_report_error(struct kasan_access_info *info) { unsigned long flags; + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); spin_lock_irqsave(&report_lock, flags); pr_err("=================================" "=================================\n"); @@ -204,12 +206,17 @@ void kasan_report_error(struct kasan_access_info *info) pr_err("=================================" "=================================\n"); spin_unlock_irqrestore(&report_lock, flags); + kasan_enable_current(); } void kasan_report_user_access(struct kasan_access_info *info) { unsigned long flags; + /* + * Make sure we don't end up in loop. + */ + kasan_disable_current(); spin_lock_irqsave(&report_lock, flags); pr_err("=================================" "=================================\n"); @@ -222,6 +229,7 @@ void kasan_report_user_access(struct kasan_access_info *info) pr_err("=================================" "=================================\n"); spin_unlock_irqrestore(&report_lock, flags); + kasan_enable_current(); } void kasan_report(unsigned long addr, size_t size, -- 2.5.0