[PATCH] libxlu: handle NULL pointer in xlu_cfg_destroy

[PATCH] libxlu: handle NULL pointer in xlu_cfg_destroy

[Olaf Hering]

Handle NULL pointer passed to xlu_cfg_destroy. libvirt calls it in its
libxlDriverConfigDispose function. If the XLU_Config was not initialized
yet for some reason a crash would occour on cleanup.
Avoid the crash just like libxl_ctx_free and xtl_logger_destroy do when
called from the same context.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ian Jackson <ian.jackson@eu.citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
---

Not sure if this is correct, or if libvirt should call this function
only if cfg is valid.

If this patch gets applied I suggest to apply this also to maintained
trees.


 tools/libxl/libxlu_cfg.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/libxl/libxlu_cfg.c b/tools/libxl/libxlu_cfg.c
index 0a59b52..1d70909 100644
--- a/tools/libxl/libxlu_cfg.c
+++ b/tools/libxl/libxlu_cfg.c
@@ -159,6 +159,7 @@ void xlu__cfg_set_free(XLU_ConfigSetting *set) {
 void xlu_cfg_destroy(XLU_Config *cfg) {
     XLU_ConfigSetting *set, *set_next;
 
+    if (!cfg) return;
     for (set= cfg->settings;
          set;
          set= set_next) {

Re: [PATCH] libxlu: handle NULL pointer in xlu_cfg_destroy

[Wei Liu]

On Thu, May 07, 2015 at 08:54:26AM +0000, Olaf Hering wrote:
> Handle NULL pointer passed to xlu_cfg_destroy. libvirt calls it in its
> libxlDriverConfigDispose function. If the XLU_Config was not initialized
> yet for some reason a crash would occour on cleanup.
> Avoid the crash just like libxl_ctx_free and xtl_logger_destroy do when
> called from the same context.
> 
> Signed-off-by: Olaf Hering <olaf@aepfle.de>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Wei Liu <wei.liu2@citrix.com>

Acked-by: Wei Liu <wei.liu2@citrix.com>

> ---
> 
> Not sure if this is correct, or if libvirt should call this function
> only if cfg is valid.
> 
> If this patch gets applied I suggest to apply this also to maintained
> trees.
> 
> 
>  tools/libxl/libxlu_cfg.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/libxl/libxlu_cfg.c b/tools/libxl/libxlu_cfg.c
> index 0a59b52..1d70909 100644
> --- a/tools/libxl/libxlu_cfg.c
> +++ b/tools/libxl/libxlu_cfg.c
> @@ -159,6 +159,7 @@ void xlu__cfg_set_free(XLU_ConfigSetting *set) {
>  void xlu_cfg_destroy(XLU_Config *cfg) {
>      XLU_ConfigSetting *set, *set_next;
>  
> +    if (!cfg) return;
>      for (set= cfg->settings;
>           set;
>           set= set_next) {

Re: [PATCH] libxlu: handle NULL pointer in xlu_cfg_destroy

[Ian Campbell]

On Thu, 2015-05-07 at 10:26 +0100, Wei Liu wrote:
> On Thu, May 07, 2015 at 08:54:26AM +0000, Olaf Hering wrote:
> > Handle NULL pointer passed to xlu_cfg_destroy. libvirt calls it in its
> > libxlDriverConfigDispose function. If the XLU_Config was not initialized
> > yet for some reason a crash would occour on cleanup.

"occur"

> > Avoid the crash just like libxl_ctx_free and xtl_logger_destroy do when
> > called from the same context.
> > 
> > Signed-off-by: Olaf Hering <olaf@aepfle.de>
> > Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> > Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > Cc: Ian Campbell <ian.campbell@citrix.com>
> > Cc: Wei Liu <wei.liu2@citrix.com>
> 
> Acked-by: Wei Liu <wei.liu2@citrix.com>

Applied, fixing the typo.

> > ---
> > 
> > Not sure if this is correct, or if libvirt should call this function
> > only if cfg is valid.
> > 
> > If this patch gets applied I suggest to apply this also to maintained
> > trees.
> > 
> > 
> >  tools/libxl/libxlu_cfg.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/tools/libxl/libxlu_cfg.c b/tools/libxl/libxlu_cfg.c
> > index 0a59b52..1d70909 100644
> > --- a/tools/libxl/libxlu_cfg.c
> > +++ b/tools/libxl/libxlu_cfg.c
> > @@ -159,6 +159,7 @@ void xlu__cfg_set_free(XLU_ConfigSetting *set) {
> >  void xlu_cfg_destroy(XLU_Config *cfg) {
> >      XLU_ConfigSetting *set, *set_next;
> >  
> > +    if (!cfg) return;
> >      for (set= cfg->settings;
> >           set;
> >           set= set_next) {