From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754170AbbIGIaK (ORCPT ); Mon, 7 Sep 2015 04:30:10 -0400 Received: from e28smtp02.in.ibm.com ([122.248.162.2]:36656 "EHLO e28smtp02.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752152AbbIGI3L (ORCPT ); Mon, 7 Sep 2015 04:29:11 -0400 X-Helo: d28dlp02.in.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, ryabinin.a.a@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" Subject: [PATCH V2 4/4] mm/kasan: Prevent deadlock in kasan reporting Date: Mon, 7 Sep 2015 13:58:39 +0530 Message-Id: <1441614519-20298-4-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1441614519-20298-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> References: <1441614519-20298-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15090708-0005-0000-0000-0000075EBEF0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we end up calling kasan_report in real mode, our shadow mapping for the 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. Reviewed-by: Andrey Ryabinin 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 c5367089703c..7833f074ede8 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