Re: [PATCH] dmaengine: ti: k3-udma: Fix NULL pointer dereference error
From: Péter Ujfalusi <peter.ujfalusi@gmail.com>
Date: 2021-02-10 10:08:31
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Hi Kishon, On 2/9/21 2:02 PM, Kishon Vijay Abraham I wrote:
bcdma_get_*() and udma_get_*() checks if bchan/rchan/tchan/rflow is
already allocated by checking if it has a NON NULL value. For the
error cases, bchan/rchan/tchan/rflow will have error value
and bcdma_get_*() 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
bchan/rchan/tchan/rflow.
Reset the value of bchan/rchan/tchan/rflow to NULL if the allocation
actually fails.
Fixes: 017794739702 ("dmaengine: ti: k3-udma: Initial support for K3 BCDMA")
Fixes: 25dcb5dd7b7c ("dmaengine: ti: New driver for K3 UDMA")
Signed-off-by: Kishon Vijay Abraham I <redacted>Is this the same patch as the other with the similar subject? -- Péter
quoted hunk ↗ jump to hunk
--- drivers/dma/ti/k3-udma.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-)diff --git a/drivers/dma/ti/k3-udma.c b/drivers/dma/ti/k3-udma.c index 298460438bb4..aa4ef583ff83 100644 --- a/drivers/dma/ti/k3-udma.c +++ b/drivers/dma/ti/k3-udma.c@@ -1330,6 +1330,7 @@ static int bcdma_get_bchan(struct udma_chan *uc) { struct udma_dev *ud = uc->ud; enum udma_tp_level tpl; + int ret; if (uc->bchan) { dev_dbg(ud->dev, "chan%d: already have bchan%d allocated\n",@@ -1347,8 +1348,11 @@ static int bcdma_get_bchan(struct udma_chan *uc) tpl = ud->bchan_tpl.levels - 1; uc->bchan = __udma_reserve_bchan(ud, tpl, -1); - if (IS_ERR(uc->bchan)) - return PTR_ERR(uc->bchan); + if (IS_ERR(uc->bchan)) { + ret = PTR_ERR(uc->bchan); + uc->bchan = NULL; + return ret; + } uc->tchan = uc->bchan;@@ -1358,6 +1362,7 @@ 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",@@ -1372,8 +1377,11 @@ 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;@@ -1403,6 +1411,7 @@ 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",@@ -1417,8 +1426,13 @@ 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)@@ -1472,6 +1486,7 @@ 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);@@ -1485,6 +1500,11 @@ 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); }