[pm:bleeding-edge 62/70] drivers/acpi/acpica/dbnames.c:576 acpi_db_walk_for_fields() error: double free of 'buffer.pointer'

[Dan Carpenter <dan.carpenter@oracle.com>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git bleeding-edge
head:   aaa43552df9b1f8c788d18df5f5989f8a13433f5
commit: 5fd033288a86676045d9e16243dfc5f988013371 [62/70] ACPICA: debugger: add command to dump all fields of particular subtype

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/acpi/acpica/dbnames.c:576 acpi_db_walk_for_fields() error: double free of 'buffer.pointer'

# https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git/commit/?id=5fd033288a86676045d9e16243dfc5f988013371
git remote add pm https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
git remote update pm
git checkout 5fd033288a86676045d9e16243dfc5f988013371
vim +576 drivers/acpi/acpica/dbnames.c

5fd033288a8667 Erik Schmauss 2019-10-25  518  static acpi_status
5fd033288a8667 Erik Schmauss 2019-10-25  519  acpi_db_walk_for_fields(acpi_handle obj_handle,
5fd033288a8667 Erik Schmauss 2019-10-25  520  			u32 nesting_level, void *context, void **return_value)
5fd033288a8667 Erik Schmauss 2019-10-25  521  {
5fd033288a8667 Erik Schmauss 2019-10-25  522  	union acpi_object *ret_value;
5fd033288a8667 Erik Schmauss 2019-10-25  523  	struct acpi_region_walk_info *info =
5fd033288a8667 Erik Schmauss 2019-10-25  524  	    (struct acpi_region_walk_info *)context;
5fd033288a8667 Erik Schmauss 2019-10-25  525  	struct acpi_buffer buffer;
5fd033288a8667 Erik Schmauss 2019-10-25  526  	acpi_status status;
5fd033288a8667 Erik Schmauss 2019-10-25  527  	struct acpi_namespace_node *node = acpi_ns_validate_handle(obj_handle);
5fd033288a8667 Erik Schmauss 2019-10-25  528  
5fd033288a8667 Erik Schmauss 2019-10-25  529  	if (!node) {
5fd033288a8667 Erik Schmauss 2019-10-25  530  		return (AE_OK);
5fd033288a8667 Erik Schmauss 2019-10-25  531  	}
5fd033288a8667 Erik Schmauss 2019-10-25  532  	if (node->object->field.region_obj->region.space_id !=
5fd033288a8667 Erik Schmauss 2019-10-25  533  	    info->address_space_id) {
5fd033288a8667 Erik Schmauss 2019-10-25  534  		return (AE_OK);
5fd033288a8667 Erik Schmauss 2019-10-25  535  	}
5fd033288a8667 Erik Schmauss 2019-10-25  536  
5fd033288a8667 Erik Schmauss 2019-10-25  537  	info->count++;
5fd033288a8667 Erik Schmauss 2019-10-25  538  
5fd033288a8667 Erik Schmauss 2019-10-25  539  	/* Get and display the full pathname to this object */
5fd033288a8667 Erik Schmauss 2019-10-25  540  
5fd033288a8667 Erik Schmauss 2019-10-25  541  	buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
5fd033288a8667 Erik Schmauss 2019-10-25  542  	status = acpi_ns_handle_to_pathname(obj_handle, &buffer, TRUE);
5fd033288a8667 Erik Schmauss 2019-10-25  543  	if (ACPI_FAILURE(status)) {
5fd033288a8667 Erik Schmauss 2019-10-25  544  		acpi_os_printf("Could Not get pathname for object %p\n",
5fd033288a8667 Erik Schmauss 2019-10-25  545  			       obj_handle);
5fd033288a8667 Erik Schmauss 2019-10-25  546  		return (AE_OK);
5fd033288a8667 Erik Schmauss 2019-10-25  547  	}
5fd033288a8667 Erik Schmauss 2019-10-25  548  
5fd033288a8667 Erik Schmauss 2019-10-25  549  	acpi_os_printf("%s ", (char *)buffer.pointer);
5fd033288a8667 Erik Schmauss 2019-10-25  550  	ACPI_FREE(buffer.pointer);

Freed here.

5fd033288a8667 Erik Schmauss 2019-10-25  551  
5fd033288a8667 Erik Schmauss 2019-10-25  552  	buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
5fd033288a8667 Erik Schmauss 2019-10-25  553  	acpi_evaluate_object(obj_handle, NULL, NULL, &buffer);

No error handling here so "buffer.pointer" isn't necessarily modified.

5fd033288a8667 Erik Schmauss 2019-10-25  554  
5fd033288a8667 Erik Schmauss 2019-10-25  555  	ret_value = (union acpi_object *)buffer.pointer;
5fd033288a8667 Erik Schmauss 2019-10-25  556  	switch (ret_value->type) {
5fd033288a8667 Erik Schmauss 2019-10-25  557  	case ACPI_TYPE_INTEGER:
5fd033288a8667 Erik Schmauss 2019-10-25  558  
5fd033288a8667 Erik Schmauss 2019-10-25  559  		acpi_os_printf("%8.8X%8.8X",
5fd033288a8667 Erik Schmauss 2019-10-25  560  			       ACPI_FORMAT_UINT64(ret_value->integer.value));
5fd033288a8667 Erik Schmauss 2019-10-25  561  		break;
5fd033288a8667 Erik Schmauss 2019-10-25  562  
5fd033288a8667 Erik Schmauss 2019-10-25  563  	case ACPI_TYPE_BUFFER:
5fd033288a8667 Erik Schmauss 2019-10-25  564  
5fd033288a8667 Erik Schmauss 2019-10-25  565  		acpi_ut_dump_buffer(ret_value->buffer.pointer,
5fd033288a8667 Erik Schmauss 2019-10-25  566  				    ret_value->buffer.length,
5fd033288a8667 Erik Schmauss 2019-10-25  567  				    DB_DISPLAY_DATA_ONLY | DB_BYTE_DISPLAY, 0);
5fd033288a8667 Erik Schmauss 2019-10-25  568  		break;
5fd033288a8667 Erik Schmauss 2019-10-25  569  
5fd033288a8667 Erik Schmauss 2019-10-25  570  	default:
5fd033288a8667 Erik Schmauss 2019-10-25  571  
5fd033288a8667 Erik Schmauss 2019-10-25  572  		break;
5fd033288a8667 Erik Schmauss 2019-10-25  573  	}
5fd033288a8667 Erik Schmauss 2019-10-25  574  	acpi_os_printf("\n");
5fd033288a8667 Erik Schmauss 2019-10-25  575  
5fd033288a8667 Erik Schmauss 2019-10-25 @576  	ACPI_FREE(buffer.pointer);

Double free.

5fd033288a8667 Erik Schmauss 2019-10-25  577  
5fd033288a8667 Erik Schmauss 2019-10-25  578  	return (AE_OK);
5fd033288a8667 Erik Schmauss 2019-10-25  579  }

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