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From:   Colin King <colin.king@canonical.com>
To:     "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Keith Busch <keith.busch@intel.com>, linux-acpi@vger.kernel.org
Cc:     kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH][next] acpi/hmat: fix uninitialized pointer dereference on pointer 'target'
Date:   Fri,  5 Apr 2019 15:12:15 +0100
Message-Id: <20190405141215.2079-1-colin.king@canonical.com>
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From: Colin Ian King <colin.king@canonical.com>

The pointer 'target' is not initialized and is only assigned when the
ACPI_HMAT_MEMORY_PD_VALID bit in p->flags is set.  There is a later null
check on target that leads to an uninitialized pointer read and
dereference when assigning target->processor_pxm when target contains a
non-null garbage value.  Fix this by initializing targer to null.

Fixes: 665ac7e92757 ("acpi/hmat: Register processor domain to its memory")
Addresses-Coverity: ("Uninitialized pointer read")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/acpi/hmat/hmat.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/hmat/hmat.c b/drivers/acpi/hmat/hmat.c
index b7824a0309f7..b275016ff648 100644
--- a/drivers/acpi/hmat/hmat.c
+++ b/drivers/acpi/hmat/hmat.c
@@ -366,7 +366,7 @@ static int __init hmat_parse_proximity_domain(union acpi_subtable_headers *heade
 					      const unsigned long end)
 {
 	struct acpi_hmat_proximity_domain *p = (void *)header;
-	struct memory_target *target;
+	struct memory_target *target = NULL;
 
 	if (p->header.length != sizeof(*p)) {
 		pr_notice("HMAT: Unexpected address range header length: %d\n",
-- 
2.20.1