2022-03-26 10:13:46

by Xiaomeng Tong

[permalink] [raw]
Subject: [PATCH v2] saa7134: fix incorrect check to determine if list is empty

The bug is here: "if (dev == NULL)".

The list iterator value will *always* be set and non-NULL by
list_for_each_entry(), so it is incorrect to assume that the iterator
value will be NULL if the list is empty. Instead, check with list_empty()
and move the 'if' ahead, to fix this bug.

Fixes: 4aabf6331f89c ("[PATCH] v4l: (951) Make saa7134-oss as a stand-alone module")
Signed-off-by: Xiaomeng Tong <[email protected]>
---
changes since v1:
- check with list_empty() (Jakob Koschel)
- and move the 'if' ahead (Xiaomeng Tong)
v1:https://lore.kernel.org/all/[email protected]/
---
drivers/media/pci/saa7134/saa7134-alsa.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/media/pci/saa7134/saa7134-alsa.c b/drivers/media/pci/saa7134/saa7134-alsa.c
index fb24d2ed3621..4955f7e7c5bf 100644
--- a/drivers/media/pci/saa7134/saa7134-alsa.c
+++ b/drivers/media/pci/saa7134/saa7134-alsa.c
@@ -1215,18 +1215,21 @@ static int alsa_device_exit(struct saa7134_dev *dev)
static int saa7134_alsa_init(void)
{
struct saa7134_dev *dev = NULL;
+ struct saa7134_dev *iter;

saa7134_dmasound_init = alsa_device_init;
saa7134_dmasound_exit = alsa_device_exit;

pr_info("saa7134 ALSA driver for DMA sound loaded\n");

- list_for_each_entry(dev, &saa7134_devlist, devlist) {
- if (dev->pci->device == PCI_DEVICE_ID_PHILIPS_SAA7130)
+ list_for_each_entry(iter, &saa7134_devlist, devlist) {
+ dev = iter;
+
+ if (iter->pci->device == PCI_DEVICE_ID_PHILIPS_SAA7130)
pr_info("%s/alsa: %s doesn't support digital audio\n",
- dev->name, saa7134_boards[dev->board].name);
+ iter->name, saa7134_boards[iter->board].name);
else
- alsa_device_init(dev);
+ alsa_device_init(iter);
}

if (dev == NULL)
--
2.17.1