[PATCH] virtio_blk: set log2blksz correctly

AKASHI Takahiro takahiro.akashi at linaro.org
Wed Aug 19 11:07:32 CEST 2020

'log2blksz' in blk_desc structure must always be initialized, otherwise
it will cause a lot of weird failures in file operations.

For example, fs_set_blk_dev[_with_part]() examines a block device against
every file system with its probe function. In particular, ext4 file
system's ext4_probe() will calls fs_devread() to fetch a super block.
If log2blksz is 0, the actual 'read' size, i.e. block_len >> log2blksz, is
much bigger than a buffer's size, and it can end up with memory corruption.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
Fixes: f4802209e59d ("virtio: Add block driver support")
 drivers/virtio/virtio_blk.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/virtio/virtio_blk.c b/drivers/virtio/virtio_blk.c
index 992118c60758..1799f5c5eb36 100644
--- a/drivers/virtio/virtio_blk.c
+++ b/drivers/virtio/virtio_blk.c
@@ -115,6 +115,7 @@ static int virtio_blk_probe(struct udevice *dev)
 		return ret;
 	desc->blksz = 512;
+	desc->log2blksz = 9;
 	virtio_cread(dev, struct virtio_blk_config, capacity, &cap);
 	desc->lba = cap;

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