From: Jiang Liu <liuj97@gmail.com>
Date: Thu, 6 Jun 2013 16:07:27 +0000 (+0800)
Subject: zram: protect sysfs handler from invalid memory access
X-Git-Tag: v3.2.49~70
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e1c3e37d2c1da620040ada44a92bdb18c4e77dd8;p=pandora-kernel.git

zram: protect sysfs handler from invalid memory access

commit 5863e10b441e7ea4b492f930f1be180a97d026f3 upstream.

Use zram->init_lock to protect access to zram->meta, otherwise it
may cause invalid memory access if zram->meta has been freed by
zram_reset_device().

This issue may be triggered by:
Thread 1:
while true; do cat mem_used_total; done
Thread 2:
while true; do echo 8M > disksize; echo 1 > reset; done

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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