Messages in this thread Patch in this message | | | From | Jiang Liu <> | Subject | [PATCH v2 08/10] zram: protect sysfs handler from invalid memory access | Date | Wed, 5 Jun 2013 00:06:06 +0800 |
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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> Cc: stable@vger.kernel.org --- 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 8cb7822..e239d94 100644 --- a/drivers/staging/zram/zram_sysfs.c +++ b/drivers/staging/zram/zram_sysfs.c @@ -179,8 +179,10 @@ static ssize_t mem_used_total_show(struct device *dev, struct zram *zram = dev_to_zram(dev); struct zram_meta *meta = zram->meta; + down_read(&zram->init_lock); if (zram->init_done) val = zs_get_total_size_bytes(meta->mem_pool); + up_read(&zram->init_lock); return sprintf(buf, "%llu\n", val); } -- 1.8.1.2
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