dmaengine: ti: k3-udma: Set r/tchan or rflow to NULL if request fail

commit eb91224e47ec33a0a32c9be0ec0fcb3433e555fd upstream.

udma_get_*() checks if rchan/tchan/rflow is already allocated by checking
if it has a NON NULL value. For the error cases, rchan/tchan/rflow will
have error value and udma_get_*() considers this as already allocated
(PASS) since the error values are NON NULL. This results in NULL pointer
dereference error while de-referencing rchan/tchan/rflow.

Reset the value of rchan/tchan/rflow to NULL if a channel request fails.

CC: stable@vger.kernel.org
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Link: https://lore.kernel.org/r/20211031032411.27235-3-kishon@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c
index 14ae288..041d8e3 100644 (file)
--- a/drivers/dma/ti/k3-udma.c
+++ b/drivers/dma/ti/k3-udma.c
@@ -1380,6 +1380,7 @@ static int bcdma_get_bchan(struct udma_chan *uc)
 static int udma_get_tchan(struct udma_chan *uc)
 {
        struct udma_dev *ud = uc->ud;
+       int ret;
 
        if (uc->tchan) {
                dev_dbg(ud->dev, "chan%d: already have tchan%d allocated\n",
@@ -1394,8 +1395,11 @@ static int udma_get_tchan(struct udma_chan *uc)
         */
        uc->tchan = __udma_reserve_tchan(ud, uc->config.channel_tpl,
                                         uc->config.mapped_channel_id);
-       if (IS_ERR(uc->tchan))
-               return PTR_ERR(uc->tchan);
+       if (IS_ERR(uc->tchan)) {
+               ret = PTR_ERR(uc->tchan);
+               uc->tchan = NULL;
+               return ret;
+       }
 
        if (ud->tflow_cnt) {
                int tflow_id;
@@ -1425,6 +1429,7 @@ static int udma_get_tchan(struct udma_chan *uc)
 static int udma_get_rchan(struct udma_chan *uc)
 {
        struct udma_dev *ud = uc->ud;
+       int ret;
 
        if (uc->rchan) {
                dev_dbg(ud->dev, "chan%d: already have rchan%d allocated\n",
@@ -1439,8 +1444,13 @@ static int udma_get_rchan(struct udma_chan *uc)
         */
        uc->rchan = __udma_reserve_rchan(ud, uc->config.channel_tpl,
                                         uc->config.mapped_channel_id);
+       if (IS_ERR(uc->rchan)) {
+               ret = PTR_ERR(uc->rchan);
+               uc->rchan = NULL;
+               return ret;
+       }
 
-       return PTR_ERR_OR_ZERO(uc->rchan);
+       return 0;
 }
 
 static int udma_get_chan_pair(struct udma_chan *uc)
@@ -1494,6 +1504,7 @@ static int udma_get_chan_pair(struct udma_chan *uc)
 static int udma_get_rflow(struct udma_chan *uc, int flow_id)
 {
        struct udma_dev *ud = uc->ud;
+       int ret;
 
        if (!uc->rchan) {
                dev_err(ud->dev, "chan%d: does not have rchan??\n", uc->id);
@@ -1507,8 +1518,13 @@ static int udma_get_rflow(struct udma_chan *uc, int flow_id)
        }
 
        uc->rflow = __udma_get_rflow(ud, flow_id);
+       if (IS_ERR(uc->rflow)) {
+               ret = PTR_ERR(uc->rflow);
+               uc->rflow = NULL;
+               return ret;
+       }
 
-       return PTR_ERR_OR_ZERO(uc->rflow);
+       return 0;
 }
 
 static void bcdma_put_bchan(struct udma_chan *uc)