From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f47.google.com (mail-pa0-f47.google.com [209.85.220.47]) by kanga.kvack.org (Postfix) with ESMTP id 3220E6B0255 for ; Mon, 7 Sep 2015 04:28:49 -0400 (EDT) Received: by pacex6 with SMTP id ex6so90589767pac.0 for ; Mon, 07 Sep 2015 01:28:48 -0700 (PDT) Received: from e28smtp09.in.ibm.com (e28smtp09.in.ibm.com. [122.248.162.9]) by mx.google.com with ESMTPS id ya7si7990381pab.157.2015.09.07.01.28.47 for (version=TLSv1 cipher=AES128-SHA bits=128/128); Mon, 07 Sep 2015 01:28:48 -0700 (PDT) Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 7 Sep 2015 13:58:44 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id 492D3394005E for ; Mon, 7 Sep 2015 13:58:42 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay03.in.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t878Sfh047186162 for ; Mon, 7 Sep 2015 13:58:41 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t878Sedw009898 for ; Mon, 7 Sep 2015 13:58:41 +0530 From: "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> 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> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, ryabinin.a.a@gmail.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" 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 -- 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