From: amanda4ray@gmail.com
To: kasan-dev <kasan-dev@googlegroups.com>
Cc: dvyukov@google.com, kcc@google.com, aryabinin@virtuozzo.com,
adech.fo@gmail.com, cl@linux.com, akpm@linux-foundation.org,
rostedt@goodmis.org, js1304@gmail.com, iamjoonsoo.kim@lge.com,
kuthonuzo.luruo@hpe.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH] kasan: avoid overflowing quarantine size on low memory systems
Date: Tue, 30 Aug 2016 19:39:14 -0700 (PDT) [thread overview]
Message-ID: <cd3db61c-a193-4a3a-a74e-7a440aa74744@googlegroups.com> (raw)
In-Reply-To: <1470063563-96266-1-git-send-email-glider@google.com>
[-- Attachment #1: Type: text/plain, Size: 3382 bytes --]
On Monday, August 1, 2016 at 10:59:29 AM UTC-4, Alexander Potapenko wrote:
> 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.
>
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Fixes: 55834c59098d ("mm: kasan: initial memory quarantine
> implementation")
> Signed-off-by: Alexander Potapenko <glider@google.com>
> ---
> mm/kasan/quarantine.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index 65793f1..416d3b0 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -196,7 +196,7 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
>
> 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 +214,15 @@ 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 (new_quarantine_size < percpu_quarantines) {
> + WARN_ONCE(1,
> + "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;
> --
> 2.8.0.rc3.226.g39d4020
On Monday, August 1, 2016 at 10:59:29 AM UTC-4, Alexander Potapenko wrote:
> 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.
>
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Fixes: 55834c59098d ("mm: kasan: initial memory quarantine
> implementation")
> Signed-off-by: Alexander Potapenko <glider@google.com>
> ---
> mm/kasan/quarantine.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index 65793f1..416d3b0 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -196,7 +196,7 @@ void quarantine_put(struct kasan_free_meta *info, struct kmem_cache *cache)
>
> 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 +214,15 @@ 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 (new_quarantine_size < percpu_quarantines) {
> + WARN_ONCE(1,
> + "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;
> --
> 2.8.0.rc3.226.g39d4020
prev parent reply other threads:[~2016-08-31 2:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-01 14:59 [PATCH] kasan: avoid overflowing quarantine size on low memory systems Alexander Potapenko
2016-08-01 20:30 ` Andrew Morton
2016-08-02 10:00 ` Andrey Ryabinin
2016-08-02 10:05 ` Dmitry Vyukov
2016-08-02 10:07 ` Alexander Potapenko
2016-08-02 10:15 ` Dmitry Vyukov
2016-08-02 10:23 ` Andrey Ryabinin
2016-08-02 10:27 ` Alexander Potapenko
2016-08-02 10:05 ` Alexander Potapenko
2016-08-31 2:39 ` amanda4ray [this message]
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