staging: vt6655: fix some erroneous memory clean-up loops

[ Upstream commit 2a2db520e3ca5aafba7c211abfd397666c9b5f9d ]

In some initialization functions of this driver, memory is allocated with
'i' acting as an index variable and increasing from 0. The commit in
"Fixes" introduces some clean-up codes in case of allocation failure,
which free memory in reverse order with 'i' decreasing to 0. However,
there are some problems:
  - The case i=0 is left out. Thus memory is leaked.
  - In case memory allocation fails right from the start, the memory
    freeing loops will start with i=-1 and invalid memory locations will
    be accessed.

One of these loops has been fixed in commit c8ff91535880 ("staging:
vt6655: fix potential memory leak"). Fix the remaining erroneous loops.

Link: https://lore.kernel.org/linux-staging/Yx9H1zSpxmNqx6Xc@kadam/
Fixes: 5341ee0adb17 ("staging: vt6655: check for memory allocation failures")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Signed-off-by: Nam Cao <namcaov@gmail.com>
Link: https://lore.kernel.org/r/20220912170429.29852-1-namcaov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index d40c2ac1492808953571d790ed085481da788abc..43e32360b6d93c399f0fcf51235288951ddc228b 100644 (file)
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -565,7 +565,7 @@ err_free_rd:
        kfree(desc->rd_info);
 
 err_free_desc:
-       while (--i) {
+       while (i--) {
                desc = &priv->aRD0Ring[i];
                device_free_rx_buf(priv, desc);
                kfree(desc->rd_info);
@@ -611,7 +611,7 @@ err_free_rd:
        kfree(desc->rd_info);
 
 err_free_desc:
-       while (--i) {
+       while (i--) {
                desc = &priv->aRD1Ring[i];
                device_free_rx_buf(priv, desc);
                kfree(desc->rd_info);
@@ -716,7 +716,7 @@ static int device_init_td1_ring(struct vnt_private *priv)
        return 0;
 
 err_free_desc:
-       while (--i) {
+       while (i--) {
                desc = &priv->apTD1Rings[i];
                kfree(desc->td_info);
        }