* [patch -next] V4L/DVB: IR/streamzap: fix usec to nsec conversion
@ 2010-10-12 6:01 Dan Carpenter
2010-10-12 13:12 ` Jarod Wilson
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2010-10-12 6:01 UTC (permalink / raw)
To: Mauro Carvalho Chehab; +Cc: Jarod Wilson, linux-media, kernel-janitors
There is an integer overflow here because 0x03000000 * 1000 is too large
for 31 bits.
rawir.duration should be in terms of nsecs.
IR_MAX_DURATION and 0x03000000 are already in terms of nsecs.
STREAMZAP_TIMEOUT and STREAMZAP_RESOLUTION are 255 and 256 respectively
and are in terms of usecs.
The original code had a deadline of 1.005 seconds and the new code has a
deadline of .065 seconds.
Signed-off-by: Dan Carpenter <error27@gmail.com>
diff --git a/drivers/media/IR/streamzap.c b/drivers/media/IR/streamzap.c
index 2cf57e6..d5d3cee 100644
--- a/drivers/media/IR/streamzap.c
+++ b/drivers/media/IR/streamzap.c
@@ -221,7 +221,7 @@ static void streamzap_callback(struct urb *urb)
struct streamzap_ir *sz;
unsigned int i;
int len;
- static int timeout = (((STREAMZAP_TIMEOUT * STREAMZAP_RESOLUTION) &
+ static int timeout = (((STREAMZAP_TIMEOUT * STREAMZAP_RESOLUTION * 1000) &
IR_MAX_DURATION) | 0x03000000);
if (!urb)
@@ -273,7 +273,7 @@ static void streamzap_callback(struct urb *urb)
struct ir_raw_event rawir;
rawir.pulse = false;
- rawir.duration = timeout * 1000;
+ rawir.duration = timeout;
sz->idle = true;
if (sz->timeout_enabled)
sz_push(sz, rawir);
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [patch -next] V4L/DVB: IR/streamzap: fix usec to nsec conversion
2010-10-12 6:01 [patch -next] V4L/DVB: IR/streamzap: fix usec to nsec conversion Dan Carpenter
@ 2010-10-12 13:12 ` Jarod Wilson
0 siblings, 0 replies; 2+ messages in thread
From: Jarod Wilson @ 2010-10-12 13:12 UTC (permalink / raw)
To: Dan Carpenter; +Cc: Mauro Carvalho Chehab, linux-media, kernel-janitors
On Tue, Oct 12, 2010 at 08:01:11AM +0200, Dan Carpenter wrote:
> There is an integer overflow here because 0x03000000 * 1000 is too large
> for 31 bits.
>
> rawir.duration should be in terms of nsecs.
> IR_MAX_DURATION and 0x03000000 are already in terms of nsecs.
> STREAMZAP_TIMEOUT and STREAMZAP_RESOLUTION are 255 and 256 respectively
> and are in terms of usecs.
>
> The original code had a deadline of 1.005 seconds and the new code has a
> deadline of .065 seconds.
>
> Signed-off-by: Dan Carpenter <error27@gmail.com>
Nice catch, fix looks good.
Acked-by: Jarod Wilson <jarod@redhat.com>
--
Jarod Wilson
jarod@redhat.com
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