Re: [Linuxwacom-devel] [PATCH] Move VCOPY storage out of the function.
On Wed, Mar 02, 2011 at 10:43:34AM -0800, Ping Cheng wrote:
> On Tue, Mar 1, 2011 at 4:33 PM, Peter Hutterer
> wrote:
>
> > Not 100% sure why this is needed but it looks like the returned address is
> > invalid, causing memory corruption. Simply moving the variable into a
> > global
> > scope fixes this issue.
> >
> > Fixes crash with server 1.7.
> >
> > Reported-by: Vu Ngoc San
> > Signed-off-by: Peter Hutterer
> > ---
> > src/wcmCommon.c |2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/src/wcmCommon.c b/src/wcmCommon.c
> > index e469e15..64e10cc 100644
> > --- a/src/wcmCommon.c
> > +++ b/src/wcmCommon.c
> > @@ -36,9 +36,9 @@
> > * data beforehand.
> > */
> > #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) < 11
> > +static int v[MAX_VALUATORS];
> > static int *VCOPY(const int *valuators, int nvals)
> > {
> > - static int v[MAX_VALUATORS];
> >memcpy(v, valuators, nvals * sizeof(int));
> >return v;
> >
>
> Once the routine is returned, the pointer is out of the scope.
>
> To return a valid pointer, the array has to be declared outside of VCOPY.
> You could declare it in the calling routine if you don't like it as a global
> variable.
well, that's the bit that is confusing me. since the storage is static, why
would the address to it be invalid (or even temporary)?
> With that said,
>
> Reviewed-by: Ping Cheng
thanks!
Cheers,
Peter
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Re: [Linuxwacom-devel] [PATCH] Move VCOPY storage out of the function.
On Tue, Mar 1, 2011 at 4:33 PM, Peter Hutterer wrote:
> Not 100% sure why this is needed but it looks like the returned address is
> invalid, causing memory corruption. Simply moving the variable into a
> global
> scope fixes this issue.
>
> Fixes crash with server 1.7.
>
> Reported-by: Vu Ngoc San
> Signed-off-by: Peter Hutterer
> ---
> src/wcmCommon.c |2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/src/wcmCommon.c b/src/wcmCommon.c
> index e469e15..64e10cc 100644
> --- a/src/wcmCommon.c
> +++ b/src/wcmCommon.c
> @@ -36,9 +36,9 @@
> * data beforehand.
> */
> #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) < 11
> +static int v[MAX_VALUATORS];
> static int *VCOPY(const int *valuators, int nvals)
> {
> - static int v[MAX_VALUATORS];
>memcpy(v, valuators, nvals * sizeof(int));
>return v;
>
Once the routine is returned, the pointer is out of the scope.
To return a valid pointer, the array has to be declared outside of VCOPY.
You could declare it in the calling routine if you don't like it as a global
variable.
With that said,
Reviewed-by: Ping Cheng
Ping
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Re: [Linuxwacom-devel] [PATCH] Move VCOPY storage out of the function.
Weird. The crash sounded like the VCOPY issue but I wouldn't have
guessed this the issue.
Reviewed-by: Chris Bagwell
Chris
On Tue, Mar 1, 2011 at 6:33 PM, Peter Hutterer wrote:
> Not 100% sure why this is needed but it looks like the returned address is
> invalid, causing memory corruption. Simply moving the variable into a global
> scope fixes this issue.
>
> Fixes crash with server 1.7.
>
> Reported-by: Vu Ngoc San
> Signed-off-by: Peter Hutterer
> ---
> src/wcmCommon.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/src/wcmCommon.c b/src/wcmCommon.c
> index e469e15..64e10cc 100644
> --- a/src/wcmCommon.c
> +++ b/src/wcmCommon.c
> @@ -36,9 +36,9 @@
> * data beforehand.
> */
> #if GET_ABI_MAJOR(ABI_XINPUT_VERSION) < 11
> +static int v[MAX_VALUATORS];
> static int *VCOPY(const int *valuators, int nvals)
> {
> - static int v[MAX_VALUATORS];
> memcpy(v, valuators, nvals * sizeof(int));
> return v;
> }
> --
> 1.7.4
>
>
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[Linuxwacom-devel] [PATCH] Move VCOPY storage out of the function.
Not 100% sure why this is needed but it looks like the returned address is
invalid, causing memory corruption. Simply moving the variable into a global
scope fixes this issue.
Fixes crash with server 1.7.
Reported-by: Vu Ngoc San
Signed-off-by: Peter Hutterer
---
src/wcmCommon.c |2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/src/wcmCommon.c b/src/wcmCommon.c
index e469e15..64e10cc 100644
--- a/src/wcmCommon.c
+++ b/src/wcmCommon.c
@@ -36,9 +36,9 @@
* data beforehand.
*/
#if GET_ABI_MAJOR(ABI_XINPUT_VERSION) < 11
+static int v[MAX_VALUATORS];
static int *VCOPY(const int *valuators, int nvals)
{
- static int v[MAX_VALUATORS];
memcpy(v, valuators, nvals * sizeof(int));
return v;
}
--
1.7.4
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