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* [Qemu-devel] [PATCH] pcie: remove duplicate assertion
@ 2016-12-23  2:16 Cao jin
  2017-01-09 22:37 ` Michael S. Tsirkin
  0 siblings, 1 reply; 3+ messages in thread
From: Cao jin @ 2016-12-23  2:16 UTC (permalink / raw)
  To: qemu-devel; +Cc: mst, marcel, qemu-trivial

"size >= 8" connote "size > 0"

Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
---
 hw/pci/pcie.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 39b10b852d91..f864c5cd5458 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -668,7 +668,6 @@ void pcie_add_capability(PCIDevice *dev,
     uint16_t next;
 
     assert(offset >= PCI_CONFIG_SPACE_SIZE);
-    assert(offset < offset + size);
     assert(offset + size <= PCIE_CONFIG_SPACE_SIZE);
     assert(size >= 8);
     assert(pci_is_express(dev));
-- 
2.1.0

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [Qemu-devel] [PATCH] pcie: remove duplicate assertion
  2016-12-23  2:16 [Qemu-devel] [PATCH] pcie: remove duplicate assertion Cao jin
@ 2017-01-09 22:37 ` Michael S. Tsirkin
  2017-01-10  8:46   ` Cao jin
  0 siblings, 1 reply; 3+ messages in thread
From: Michael S. Tsirkin @ 2017-01-09 22:37 UTC (permalink / raw)
  To: Cao jin; +Cc: qemu-devel, marcel, qemu-trivial

On Fri, Dec 23, 2016 at 10:16:30AM +0800, Cao jin wrote:
> "size >= 8" connote "size > 0"
> 
> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>

Isn't the point to check for overflows?

> ---
>  hw/pci/pcie.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
> index 39b10b852d91..f864c5cd5458 100644
> --- a/hw/pci/pcie.c
> +++ b/hw/pci/pcie.c
> @@ -668,7 +668,6 @@ void pcie_add_capability(PCIDevice *dev,
>      uint16_t next;
>  
>      assert(offset >= PCI_CONFIG_SPACE_SIZE);
> -    assert(offset < offset + size);
>      assert(offset + size <= PCIE_CONFIG_SPACE_SIZE);
>      assert(size >= 8);
>      assert(pci_is_express(dev));
> -- 
> 2.1.0
> 
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [Qemu-devel] [PATCH] pcie: remove duplicate assertion
  2017-01-09 22:37 ` Michael S. Tsirkin
@ 2017-01-10  8:46   ` Cao jin
  0 siblings, 0 replies; 3+ messages in thread
From: Cao jin @ 2017-01-10  8:46 UTC (permalink / raw)
  To: Michael S. Tsirkin; +Cc: qemu-devel, marcel, qemu-trivial



On 01/10/2017 06:37 AM, Michael S. Tsirkin wrote:
> On Fri, Dec 23, 2016 at 10:16:30AM +0800, Cao jin wrote:
>> "size >= 8" connote "size > 0"
>>
>> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
> 
> Isn't the point to check for overflows?
> 

Make sense. If it is intended to check overflows, the following sequence
would make more sense:

    assert(offset >= PCI_CONFIG_SPACE_SIZE);
    assert(size >= 8);
    assert(offset < offset + size);
    assert(offset + size <= PCIE_CONFIG_SPACE_SIZE);

or else, size 0 will pass the assert(offset < offset + size) first and
hit assert(size >= 8)
-- 
Sincerely,
Cao jin

>> ---
>>  hw/pci/pcie.c | 1 -
>>  1 file changed, 1 deletion(-)
>>
>> diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
>> index 39b10b852d91..f864c5cd5458 100644
>> --- a/hw/pci/pcie.c
>> +++ b/hw/pci/pcie.c
>> @@ -668,7 +668,6 @@ void pcie_add_capability(PCIDevice *dev,
>>      uint16_t next;
>>  
>>      assert(offset >= PCI_CONFIG_SPACE_SIZE);
>> -    assert(offset < offset + size);
>>      assert(offset + size <= PCIE_CONFIG_SPACE_SIZE);
>>      assert(size >= 8);
>>      assert(pci_is_express(dev));
>> -- 
>> 2.1.0
>>
>>
> 
> 
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2017-01-10  8:40 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2016-12-23  2:16 [Qemu-devel] [PATCH] pcie: remove duplicate assertion Cao jin
2017-01-09 22:37 ` Michael S. Tsirkin
2017-01-10  8:46   ` Cao jin

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