From d2e7d079c7f21999e93802351c6ac7b31d266cce Mon Sep 17 00:00:00 2001 From: "David E. Box" Date: Mon, 23 Sep 2013 09:52:12 +0800 Subject: [PATCH] ACPICA: Operation region support: Never free the handler "context" pointer. This change removes some dangerous code that attempts to free the handler context pointer in some (rare) circumstances. The owner of the handler owns this pointer and the ACPICA code should never touch it. Although not seen to be an issue in any kernel, it did show up as a problem under AcpiExec. Also, set the internal storage field for the context pointer to zero when the region is deactivated, simply for sanity. David Box. Signed-off-by: David E. Box Signed-off-by: Bob Moore Signed-off-by: Lv Zheng Reviewed-by: Len Brown Signed-off-by: Rafael J. Wysocki --- drivers/acpi/acpica/evregion.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/acpi/acpica/evregion.c b/drivers/acpi/acpica/evregion.c index cea14d6fc76c..6293d6bb6fe1 100644 --- a/drivers/acpi/acpica/evregion.c +++ b/drivers/acpi/acpica/evregion.c @@ -217,16 +217,11 @@ acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj, if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE)) { region_obj->region.flags |= AOPOBJ_SETUP_COMPLETE; - if (region_obj2->extra.region_context) { - - /* The handler for this region was already installed */ - - ACPI_FREE(region_context); - } else { - /* - * Save the returned context for use in all accesses to - * this particular region - */ + /* + * Save the returned context for use in all accesses to + * the handler for this particular region + */ + if (!(region_obj2->extra.region_context)) { region_obj2->extra.region_context = region_context; } @@ -402,6 +397,14 @@ acpi_ev_detach_region(union acpi_operand_object *region_obj, handler_obj->address_space. context, region_context); + /* + * region_context should have been released by the deactivate + * operation. We don't need access to it anymore here. + */ + if (region_context) { + *region_context = NULL; + } + /* Init routine may fail, Just ignore errors */ if (ACPI_FAILURE(status)) { -- 2.20.1