From: Minchan Kim <minchan@kernel.org>
To: Weijie Yang <weijie.yang@samsung.com>
Cc: 'Andrew Morton' <akpm@linux-foundation.org>,
'Dan Streetman' <ddstreet@ieee.org>,
'Sergey Senozhatsky' <sergey.senozhatsky@gmail.com>,
'Nitin Gupta' <ngupta@vflare.org>,
'Linux-MM' <linux-mm@kvack.org>,
'linux-kernel' <linux-kernel@vger.kernel.org>,
'Weijie Yang' <weijie.yang.kh@gmail.com>
Subject: Re: [PATCH 2/2] zram: avoid NULL pointer access when reading mem_used_total
Date: Sun, 26 Oct 2014 10:44:50 +0900 [thread overview]
Message-ID: <20141026014450.GB3328@gmail.com> (raw)
In-Reply-To: <000101cff035$d9f50480$8ddf0d80$%yang@samsung.com>
On Sat, Oct 25, 2014 at 05:26:31PM +0800, Weijie Yang wrote:
> There is a rare NULL pointer bug in mem_used_total_show() in concurrent
> situation, like this:
> zram is not initialized, process A is a mem_used_total reader which runs
> periodicity, while process B try to init zram.
>
> process A process B
> access meta, get a NULL value
> init zram, done
> init_done() is true
> access meta->mem_pool, get a NULL pointer BUG
>
> This patch fixes this issue.
>
> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Thanks!
--
Kind regards,
Minchan Kim
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WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan@kernel.org>
To: Weijie Yang <weijie.yang@samsung.com>
Cc: "'Andrew Morton'" <akpm@linux-foundation.org>,
"'Dan Streetman'" <ddstreet@ieee.org>,
"'Sergey Senozhatsky'" <sergey.senozhatsky@gmail.com>,
"'Nitin Gupta'" <ngupta@vflare.org>,
"'Linux-MM'" <linux-mm@kvack.org>,
"'linux-kernel'" <linux-kernel@vger.kernel.org>,
"'Weijie Yang'" <weijie.yang.kh@gmail.com>
Subject: Re: [PATCH 2/2] zram: avoid NULL pointer access when reading mem_used_total
Date: Sun, 26 Oct 2014 10:44:50 +0900 [thread overview]
Message-ID: <20141026014450.GB3328@gmail.com> (raw)
In-Reply-To: <000101cff035$d9f50480$8ddf0d80$%yang@samsung.com>
On Sat, Oct 25, 2014 at 05:26:31PM +0800, Weijie Yang wrote:
> There is a rare NULL pointer bug in mem_used_total_show() in concurrent
> situation, like this:
> zram is not initialized, process A is a mem_used_total reader which runs
> periodicity, while process B try to init zram.
>
> process A process B
> access meta, get a NULL value
> init zram, done
> init_done() is true
> access meta->mem_pool, get a NULL pointer BUG
>
> This patch fixes this issue.
>
> Signed-off-by: Weijie Yang <weijie.yang@samsung.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Thanks!
--
Kind regards,
Minchan Kim
next prev parent reply other threads:[~2014-10-26 1:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-25 9:26 [PATCH 2/2] zram: avoid NULL pointer access when reading mem_used_total Weijie Yang
2014-10-25 9:26 ` Weijie Yang
2014-10-26 1:44 ` Minchan Kim [this message]
2014-10-26 1:44 ` Minchan Kim
2014-10-26 5:41 ` Sergey Senozhatsky
2014-10-26 5:41 ` Sergey Senozhatsky
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