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From:   "Rafael J. Wysocki" <rjw@rjwysocki.net>
To:     Linux ACPI <linux-acpi@vger.kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Vicki Pfau <vi@endrift.com>
Subject: [PATCH v1] ACPI: utils: Fix error path in acpi_evaluate_reference()
Date:   Thu, 07 Dec 2023 19:28:10 +0100
Message-ID: <12343148.O9o76ZdvQC@kreacher>
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If a pointer to an uninitialized struct acpi_handle_list is passed to
acpi_evaluate_reference() and it decides to bail out early, either
because acpi_evaluate_object() fails, or because it produces invalid
data, the handles pointer from the struct acpi_handle_list will be
passed to kfree() and if it is not NULL, the kernel will crash.

Address this by moving the "end" label in acpi_evaluate_reference() to
the end of the function, which is sufficient, because no cleanup is
needed in that case.

Fixes: 2e57d10a6591 ("ACPI: utils: Dynamically determine acpi_handle_list size")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/acpi/utils.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/utils.c
===================================================================
--- linux-pm.orig/drivers/acpi/utils.c
+++ linux-pm/drivers/acpi/utils.c
@@ -399,13 +399,13 @@ acpi_evaluate_reference(acpi_handle hand
 		acpi_handle_debug(list->handles[i], "Found in reference list\n");
 	}
 
-end:
 	if (ACPI_FAILURE(status)) {
 		list->count = 0;
 		kfree(list->handles);
 		list->handles = NULL;
 	}
 
+end:
 	kfree(buffer.pointer);
 
 	return status;