* [PATCH] usb: core: Do not use sizeof on pointer type
@ 2016-04-22 5:51 Vaishali Thakkar
2016-04-22 6:53 ` Clemens Ladisch
2016-04-22 6:57 ` Bjørn Mork
0 siblings, 2 replies; 3+ messages in thread
From: Vaishali Thakkar @ 2016-04-22 5:51 UTC (permalink / raw)
To: gregkh; +Cc: linux-usb, linux-kernel, Vaishali Thakkar
When sizeof is applied to a pointer typed expression, it gives
the size of the pointer. So, do not use sizeof on pointer type.
Problem found using Coccinelle.
Signed-off-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
---
drivers/usb/core/hcd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 2ca2cef..2aa352d 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1386,7 +1386,7 @@ static int hcd_alloc_coherent(struct usb_bus *bus,
return -EFAULT;
}
- vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
+ vaddr = hcd_buffer_alloc(bus, size + sizeof(*vaddr),
mem_flags, dma_handle);
if (!vaddr)
return -ENOMEM;
--
2.1.4
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] usb: core: Do not use sizeof on pointer type
2016-04-22 5:51 [PATCH] usb: core: Do not use sizeof on pointer type Vaishali Thakkar
@ 2016-04-22 6:53 ` Clemens Ladisch
2016-04-22 6:57 ` Bjørn Mork
1 sibling, 0 replies; 3+ messages in thread
From: Clemens Ladisch @ 2016-04-22 6:53 UTC (permalink / raw)
To: Vaishali Thakkar; +Cc: gregkh, linux-usb, linux-kernel
Vaishali Thakkar wrote:
> When sizeof is applied to a pointer typed expression, it gives
> the size of the pointer.
And why would that be wrong in this case?
> +++ b/drivers/usb/core/hcd.c
> @@ -1386,7 +1386,7 @@ static int hcd_alloc_coherent(struct usb_bus *bus,
> return -EFAULT;
> }
>
> - vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
> + vaddr = hcd_buffer_alloc(bus, size + sizeof(*vaddr),
> mem_flags, dma_handle);
> if (!vaddr)
> return -ENOMEM;
>
Please note the following comment:
/*
* Store the virtual address of the buffer at the end
* of the allocated dma buffer. [...]
Regards,
Clemens
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] usb: core: Do not use sizeof on pointer type
2016-04-22 5:51 [PATCH] usb: core: Do not use sizeof on pointer type Vaishali Thakkar
2016-04-22 6:53 ` Clemens Ladisch
@ 2016-04-22 6:57 ` Bjørn Mork
1 sibling, 0 replies; 3+ messages in thread
From: Bjørn Mork @ 2016-04-22 6:57 UTC (permalink / raw)
To: Vaishali Thakkar; +Cc: gregkh, linux-usb, linux-kernel
Vaishali Thakkar <vaishali.thakkar@oracle.com> writes:
> When sizeof is applied to a pointer typed expression, it gives
> the size of the pointer. So, do not use sizeof on pointer type.
What if the intended result was the size of the pointer?
> Problem found using Coccinelle.
Yes, sure. But you cannot just blindly apply the result without reading
and understanding the code.
Bjørn
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-04-22 5:51 [PATCH] usb: core: Do not use sizeof on pointer type Vaishali Thakkar
2016-04-22 6:53 ` Clemens Ladisch
2016-04-22 6:57 ` Bjørn Mork
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