From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56479 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752744AbcI1Iix (ORCPT ); Wed, 28 Sep 2016 04:38:53 -0400 Subject: Patch "kasan: avoid overflowing quarantine size on low memory systems" has been added to the 4.7-stable tree To: glider@google.com, akpm@linux-foundation.org, aryabinin@virtuozzo.com, dvyukov@google.com, gregkh@linuxfoundation.org, torvalds@linux-foundation.org Cc: , From: Date: Wed, 28 Sep 2016 10:38:36 +0200 Message-ID: <147505191619594@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled kasan: avoid overflowing quarantine size on low memory systems to the 4.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kasan-avoid-overflowing-quarantine-size-on-low-memory-systems.patch and it can be found in the queue-4.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From c3cee372282cb6bcdf19ac1457581d5dd5ecb554 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Tue, 2 Aug 2016 14:02:58 -0700 Subject: kasan: avoid overflowing quarantine size on low memory systems From: Alexander Potapenko commit c3cee372282cb6bcdf19ac1457581d5dd5ecb554 upstream. If the total amount of memory assigned to quarantine is less than the amount of memory assigned to per-cpu quarantines, |new_quarantine_size| may overflow. Instead, set it to zero. [akpm@linux-foundation.org: cleanup: use WARN_ONCE return value] Link: http://lkml.kernel.org/r/1470063563-96266-1-git-send-email-glider@google.com Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation") Signed-off-by: Alexander Potapenko Reported-by: Dmitry Vyukov Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/kasan/quarantine.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/mm/kasan/quarantine.c +++ b/mm/kasan/quarantine.c @@ -196,7 +196,7 @@ void quarantine_put(struct kasan_free_me void quarantine_reduce(void) { - size_t new_quarantine_size; + size_t new_quarantine_size, percpu_quarantines; unsigned long flags; struct qlist_head to_free = QLIST_INIT; size_t size_to_free = 0; @@ -214,7 +214,12 @@ void quarantine_reduce(void) */ new_quarantine_size = (READ_ONCE(totalram_pages) << PAGE_SHIFT) / QUARANTINE_FRACTION; - new_quarantine_size -= QUARANTINE_PERCPU_SIZE * num_online_cpus(); + percpu_quarantines = QUARANTINE_PERCPU_SIZE * num_online_cpus(); + if (WARN_ONCE(new_quarantine_size < percpu_quarantines, + "Too little memory, disabling global KASAN quarantine.\n")) + new_quarantine_size = 0; + else + new_quarantine_size -= percpu_quarantines; WRITE_ONCE(quarantine_size, new_quarantine_size); last = global_quarantine.head; Patches currently in stable-queue which might be from glider@google.com are queue-4.7/mm-kasan-don-t-reduce-quarantine-in-atomic-contexts.patch queue-4.7/kasan-avoid-overflowing-quarantine-size-on-low-memory-systems.patch