> From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
>
> Stop referencing 'features' memory after release_firmware is called.
>
> Fixes this crash:
>
> RIP: 0010:mt7921_check_offload_capability+0x17d
> mt7921_pci_probe+0xca/0x4b0
> ...
>
> Signed-off-by: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Acked-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
> ---
> drivers/net/wireless/mediatek/mt76/mt7921/init.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/init.c b/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> index 38d6563cb12f..d2bb8d02ce0a 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/init.c
> @@ -165,12 +165,12 @@ mt7921_mac_init_band(struct mt7921_dev *dev, u8 band)
>
> u8 mt7921_check_offload_capability(struct device *dev, const char *fw_wm)
> {
> - struct mt7921_fw_features *features = NULL;
> const struct mt76_connac2_fw_trailer *hdr;
> struct mt7921_realease_info *rel_info;
> const struct firmware *fw;
> int ret, i, offset = 0;
> const u8 *data, *end;
> + u8 offload_caps = 0;
>
> ret = request_firmware(&fw, fw_wm, dev);
> if (ret)
> @@ -197,12 +197,19 @@ u8 mt7921_check_offload_capability(struct device *dev, const char *fw_wm)
> data += sizeof(*rel_info);
> end = data + le16_to_cpu(rel_info->len);
>
> + /* TODO: This needs better sanity checking I think.
> + * Likely a corrupted firmware with bad rel_info->len, for instance,
> + * would blow this up.
> + */
> while (data < end) {
> rel_info = (struct mt7921_realease_info *)data;
> data += sizeof(*rel_info);
>
> if (rel_info->tag == MT7921_FW_TAG_FEATURE) {
> + struct mt7921_fw_features *features;
> +
> features = (struct mt7921_fw_features *)data;
> + offload_caps = features->data;
> break;
> }
>
> @@ -211,7 +218,7 @@ u8 mt7921_check_offload_capability(struct device *dev, const char *fw_wm)
>
> release_firmware(fw);
>
> - return features ? features->data : 0;
> + return offload_caps;
> }
> EXPORT_SYMBOL_GPL(mt7921_check_offload_capability);
>
> --
> 2.39.1
>
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