Messages in this thread Patch in this message | | | From | Jiang Liu <> | Subject | [PATCH v2 02/10] zram: avoid invalid memory access in zram_exit() | Date | Wed, 5 Jun 2013 00:06:00 +0800 |
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Memory for zram->disk object may have already been freed after returning from destroy_device(zram), then it's unsafe for zram_reset_device(zram) to access zram->disk again.
We can't solve this bug by flipping the order of destroy_device(zram) and zram_reset_device(zram), that will cause deadlock issues to the zram sysfs handler.
So fix it by holding an extra reference to zram->disk before calling destroy_device(zram).
Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: stable@vger.kernel.org --- drivers/staging/zram/zram_drv.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 0a07de4..5a2f20b 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -722,8 +722,10 @@ static void __exit zram_exit(void) for (i = 0; i < num_devices; i++) { zram = &zram_devices[i]; + get_disk(zram->disk); destroy_device(zram); zram_reset_device(zram); + put_disk(zram->disk); } unregister_blkdev(zram_major, "zram"); -- 1.8.1.2
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