Re: [PATCH] c8sectpfe: fix potential NULL pointer dereference in c8sectpfe_timer_interrupt

From: Gustavo A. R. Silva
Date: Wed Nov 22 2017 - 09:21:13 EST

On 11/21/2017 02:22 AM, Patrice CHOTARD wrote:
Hi Gustavo

On 11/20/2017 03:00 PM, Gustavo A. R. Silva wrote:
_channel_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference. Fix this by moving the pointer dereference
after _channel_ has been null checked.

This issue was detected with the help of Coccinelle.

Fixes: c5f5d0f99794 ("[media] c8sectpfe: STiH407/10 Linux DVB demux support")
Signed-off-by: Gustavo A. R. Silva <garsilva@xxxxxxxxxxxxxx>
drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c b/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
index 59280ac..23d0ced 100644
--- a/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
+++ b/drivers/media/platform/sti/c8sectpfe/c8sectpfe-core.c
@@ -83,7 +83,7 @@ static void c8sectpfe_timer_interrupt(unsigned long ac8sectpfei)
static void channel_swdemux_tsklet(unsigned long data)
struct channel_info *channel = (struct channel_info *)data;
- struct c8sectpfei *fei = channel->fei;
+ struct c8sectpfei *fei;
unsigned long wp, rp;
int pos, num_packets, n, size;
u8 *buf;
@@ -91,6 +91,8 @@ static void channel_swdemux_tsklet(unsigned long data)
if (unlikely(!channel || !channel->irec))
+ fei = channel->fei;
wp = readl(channel->irec + DMA_PRDS_BUSWP_TP(0));
rp = readl(channel->irec + DMA_PRDS_BUSRP_TP(0));

Acked-by: Patrice Chotard <patrice.chotard@xxxxxx>


Thank you, Patrice.

Gustavo A. R. Silva