From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jiang Liu , Greg Kroah-Hartman , Luis Henriques Subject: [PATCH 013/145] zram: protect sysfs handler from invalid memory access Date: Wed, 17 Jul 2013 15:45:45 -0700 Message-Id: <1374101277-7915-14-git-send-email-kamal@canonical.com> In-Reply-To: <1374101277-7915-1-git-send-email-kamal@canonical.com> References: <1374101277-7915-1-git-send-email-kamal@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.8.13.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Liu 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 Acked-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman [ luis: backported to 3.8: - protect access to zram->mem_pool instead of zram->meta ] Signed-off-by: Luis Henriques --- drivers/staging/zram/zram_sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/staging/zram/zram_sysfs.c b/drivers/staging/zram/zram_sysfs.c index de1eacf..c07687e 100644 --- a/drivers/staging/zram/zram_sysfs.c +++ b/drivers/staging/zram/zram_sysfs.c @@ -186,8 +186,10 @@ static ssize_t mem_used_total_show(struct device *dev, u64 val = 0; struct zram *zram = dev_to_zram(dev); + down_read(&zram->init_lock); if (zram->init_done) val = zs_get_total_size_bytes(zram->mem_pool); + up_read(&zram->init_lock); return sprintf(buf, "%llu\n", val); } -- 1.8.1.2