Re: [Qemu-devel] [PATCH for 1.2] console: Fix warning from clang (and potential crash)

[Anthony Liguori]

Stefan Weil  writes:

> Am 17.08.2012 16:10, schrieb Jan Kiszka:
>> On 2012-08-17 15:50, Stefan Weil wrote:
>>
>>> ccc-analyzer reports this warning:
>>>
>>> console.c:1090:29: warning: Dereference of null pointer
>>>  if (active_console->cursor_timer) {
>>>  ^
>>>
>>> Function console_select allows active_console to be NULL,
>>> but would crash when accessing cursor_timer. Fix this.
>>>
>>> Signed-off-by: Stefan Weil
>>> ---
>>>
>>> Please note that I don't have a test case which triggers the crash.
>>>
>>> Regards,
>>> Stefan Weil
>>>
>>>   console.c |2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/console.c b/console.c
>>> index 4525cc7..f5e8814 100644
>>> --- a/console.c
>>> +++ b/console.c
>>> @@ -1087,7 +1087,7 @@ void console_select(unsigned int index)
>>>   if (s) {
>>>   DisplayState *ds = s->ds;
>>>
>>> -if (active_console->cursor_timer) {
>>> +if (active_console&&  active_console->cursor_timer) {
>>>   qemu_del_timer(active_console->cursor_timer);
>>>   }
>>>   active_console = s;
>>>
>>>  
>> The only path that could trigger this is console_select() in the absence
>> of any console. Not sure if that is possible, but the above is surely
>> consistent with existing code.
>>
>> Reviewed-by: Jan Kiszka
>>
>> Jan
>>
>>
>
>
> Ping? It's still missing in QEMU 1.2.

It'll need to wait for 1.3 to open up.  I missed it for 1.2-rc2 and at
this point, I don't want to commit anything other than actual bug fixes.

Regards,

Anthony Liguori

Re: [Qemu-devel] [PATCH for 1.2] console: Fix warning from clang (and potential crash)

[Stefan Weil]

Am 17.08.2012 16:10, schrieb Jan Kiszka:

On 2012-08-17 15:50, Stefan Weil wrote:
   

ccc-analyzer reports this warning:

console.c:1090:29: warning: Dereference of null pointer
 if (active_console->cursor_timer) {
 ^

Function console_select allows active_console to be NULL,
but would crash when accessing cursor_timer. Fix this.

Signed-off-by: Stefan Weil
---

Please note that I don't have a test case which triggers the crash.

Regards,
Stefan Weil

  console.c |2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/console.c b/console.c
index 4525cc7..f5e8814 100644
--- a/console.c
+++ b/console.c
@@ -1087,7 +1087,7 @@ void console_select(unsigned int index)
  if (s) {
  DisplayState *ds = s->ds;

-if (active_console->cursor_timer) {
+if (active_console&&  active_console->cursor_timer) {
  qemu_del_timer(active_console->cursor_timer);
  }
  active_console = s;

 

The only path that could trigger this is console_select() in the absence
of any console. Not sure if that is possible, but the above is surely
consistent with existing code.

Reviewed-by: Jan Kiszka

Jan

   



Ping? It's still missing in QEMU 1.2.

Re: [Qemu-devel] [PATCH for 1.2] console: Fix warning from clang (and potential crash)

[Jan Kiszka]

On 2012-08-17 15:50, Stefan Weil wrote:
> ccc-analyzer reports this warning:
> 
> console.c:1090:29: warning: Dereference of null pointer
> if (active_console->cursor_timer) {
> ^
> 
> Function console_select allows active_console to be NULL,
> but would crash when accessing cursor_timer. Fix this.
> 
> Signed-off-by: Stefan Weil 
> ---
> 
> Please note that I don't have a test case which triggers the crash.
> 
> Regards,
> Stefan Weil
> 
>  console.c |2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/console.c b/console.c
> index 4525cc7..f5e8814 100644
> --- a/console.c
> +++ b/console.c
> @@ -1087,7 +1087,7 @@ void console_select(unsigned int index)
>  if (s) {
>  DisplayState *ds = s->ds;
>  
> -if (active_console->cursor_timer) {
> +if (active_console && active_console->cursor_timer) {
>  qemu_del_timer(active_console->cursor_timer);
>  }
>  active_console = s;
> 

The only path that could trigger this is console_select() in the absence
of any console. Not sure if that is possible, but the above is surely
consistent with existing code.

Reviewed-by: Jan Kiszka 

Jan

-- 
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux

[Qemu-devel] [PATCH for 1.2] console: Fix warning from clang (and potential crash)

[Stefan Weil]

ccc-analyzer reports this warning:

console.c:1090:29: warning: Dereference of null pointer
if (active_console->cursor_timer) {
^

Function console_select allows active_console to be NULL,
but would crash when accessing cursor_timer. Fix this.

Signed-off-by: Stefan Weil 
---

Please note that I don't have a test case which triggers the crash.

Regards,
Stefan Weil

 console.c |2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/console.c b/console.c
index 4525cc7..f5e8814 100644
--- a/console.c
+++ b/console.c
@@ -1087,7 +1087,7 @@ void console_select(unsigned int index)
 if (s) {
 DisplayState *ds = s->ds;
 
-if (active_console->cursor_timer) {
+if (active_console && active_console->cursor_timer) {
 qemu_del_timer(active_console->cursor_timer);
 }
 active_console = s;
-- 
1.7.10