From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id DC0936B0005 for ; Wed, 2 May 2018 06:58:43 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id x23so5246549pfm.7 for ; Wed, 02 May 2018 03:58:43 -0700 (PDT) Received: from www262.sakura.ne.jp (www262.sakura.ne.jp. [202.181.97.72]) by mx.google.com with ESMTPS id q22-v6si1112783pgc.150.2018.05.02.03.58.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 May 2018 03:58:42 -0700 (PDT) From: Tetsuo Handa Subject: [PATCH] kasan: record timestamp of memory allocation/free Date: Wed, 2 May 2018 19:58:09 +0900 Message-Id: <1525258689-3430-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> Sender: owner-linux-mm@kvack.org List-ID: To: kasan-dev@googlegroups.com Cc: linux-mm@kvack.org, Tetsuo Handa , Alexander Potapenko , Andrey Konovalov , Andrey Ryabinin , Christoph Lameter , David Rientjes , Dmitry Chernenkov , Dmitry Vyukov , Joonsoo Kim , Konstantin Serebryany , Pekka Enberg , Steven Rostedt syzbot is reporting many refcount/use-after-free bugs along with flood of memory allocation fault injection messages. Showing timestamp of memory allocation/free would help narrowing down kernel messages to examine. Revive timestamp field which was removed by commit cd11016e5f5212c1 ("mm, kasan: stackdepot implementation. Enable stackdepot for SLAB"). Signed-off-by: Tetsuo Handa Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Steven Rostedt Cc: Konstantin Serebryany Cc: Dmitry Chernenkov --- mm/kasan/kasan.c | 1 + mm/kasan/kasan.h | 1 + mm/kasan/report.c | 3 ++- 3 files changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/kasan/kasan.c b/mm/kasan/kasan.c index 135ce28..a336834 100644 --- a/mm/kasan/kasan.c +++ b/mm/kasan/kasan.c @@ -457,6 +457,7 @@ static inline depot_stack_handle_t save_stack(gfp_t flags) static inline void set_track(struct kasan_track *track, gfp_t flags) { track->pid = current->pid; + track->when = jiffies; track->stack = save_stack(flags); } diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index c12dcfd..0e4951b 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -77,6 +77,7 @@ struct kasan_global { struct kasan_track { u32 pid; depot_stack_handle_t stack; + unsigned long when; }; struct kasan_alloc_meta { diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 5c169aa..062c8ae 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -183,7 +183,8 @@ static void kasan_end_report(unsigned long *flags) static void print_track(struct kasan_track *track, const char *prefix) { - pr_err("%s by task %u:\n", prefix, track->pid); + pr_err("%s by task %u (%lu jiffies ago):\n", prefix, track->pid, + jiffies - track->when); if (track->stack) { struct stack_trace trace; -- 1.8.3.1