From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130911042917.296227051@goodmis.org> Date: Wed, 11 Sep 2013 00:29:37 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiang Liu , Minchan Kim , Greg Kroah-Hartman Subject: [150/251] zram: protect sysfs handler from invalid memory access References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0150-zram-protect-sysfs-handler-from-invalid-memory-acces.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiang Liu [ Upstream commit 5863e10b441e7ea4b492f930f1be180a97d026f3 ] 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 Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Steven Rostedt --- 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 edb0ed4..5e07628 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); } -- 1.7.10.4