[PATCH] dmar: Fix double free in error paths following c/s a8bc99b

[PATCH] dmar: Fix double free in error paths following c/s a8bc99b

[Andrew Cooper]

Several error paths would end up freeing scope->devices twice.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Elena Ufimtseva <elena.ufimtseva@oracle.com>
CC: Yang Zhang <yang.z.zhang@intel.com>
CC: Kevin Tian <kevin.tian@intel.com>
---
 xen/drivers/passthrough/vtd/dmar.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/xen/drivers/passthrough/vtd/dmar.c b/xen/drivers/passthrough/vtd/dmar.c
index 8ed1e24..2672688 100644
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -88,6 +88,7 @@ static void scope_devices_free(struct dmar_scope *scope)
 
     scope->devices_cnt = 0;
     xfree(scope->devices);
+    scope->devices = NULL;
 }
 
 static void __init disable_all_dmar_units(void)
-- 
1.7.10.4

Re: [PATCH] dmar: Fix double free in error paths following c/s a8bc99b

[Jan Beulich]

>>> On 16.07.15 at 13:57, <andrew.cooper3@citrix.com> wrote:
> Several error paths would end up freeing scope->devices twice.

Of course it depends how you count, but I can spot exactly one
broken case - in acpi_parse_dev_scope(). All other callers of
scope_devices_free() free the container right afterwards afaics.

Jan

Re: [PATCH] dmar: Fix double free in error paths following c/s a8bc99b

[Tian, Kevin]

> From: Andrew Cooper [mailto:andrew.cooper3@citrix.com]
> Sent: Thursday, July 16, 2015 7:57 PM
> 
> Several error paths would end up freeing scope->devices twice.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Jan Beulich <JBeulich@suse.com>
> CC: Elena Ufimtseva <elena.ufimtseva@oracle.com>
> CC: Yang Zhang <yang.z.zhang@intel.com>
> CC: Kevin Tian <kevin.tian@intel.com>

Acked-by: Kevin Tian <kevin.tian@intel.com>

> ---
>  xen/drivers/passthrough/vtd/dmar.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/xen/drivers/passthrough/vtd/dmar.c b/xen/drivers/passthrough/vtd/dmar.c
> index 8ed1e24..2672688 100644
> --- a/xen/drivers/passthrough/vtd/dmar.c
> +++ b/xen/drivers/passthrough/vtd/dmar.c
> @@ -88,6 +88,7 @@ static void scope_devices_free(struct dmar_scope *scope)
> 
>      scope->devices_cnt = 0;
>      xfree(scope->devices);
> +    scope->devices = NULL;
>  }
> 
>  static void __init disable_all_dmar_units(void)
> --
> 1.7.10.4