Patch "firmware: dmi_scan: Fix ordering of product_uuid" has been added to the 4.0-stable tree

This is a note to let you know that I've just added the patch titled

firmware: dmi_scan: Fix ordering of product_uuid

to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
firmware-dmi_scan-fix-ordering-of-product_uuid.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jean Delvare <[email protected]>
Date: Thu, 14 May 2015 14:40:50 +0200
Subject: firmware: dmi_scan: Fix ordering of product_uuid

From: Jean Delvare <[email protected]>

commit 5c1ac56b51b9d222ab202dec1ac2f4215346129d upstream.

In function dmi_present(), dmi_walk_early() calls dmi_table(), which calls dmi_decode(), which ultimately calls dmi_save_uuid(). This last function makes a decision based on the value of global variable dmi_ver. The problem is that this variable is set right _after_ dmi_walk_early() returns. So dmi_save_uuid() always sees dmi_ver == 0 regardless of the actual version implemented.

This causes /sys/class/dmi/id/product_uuid to always use the old ordering even on systems implementing DMI/SMBIOS 2.6 or later, which should use the new ordering.

This is broken since kernel v3.8 for legacy DMI implementations and since kernel v3.10 for SMBIOS 2 implementations. SMBIOS 3 implementations with the 64-bit entry point are not affected.

The first breakage does not matter much as in practice legacy DMI implementations are always for versions older than 2.6, which is when the UUID ordering changed. The second breakage is more problematic as it affects the vast majority of x86 systems manufactured since 2009.

---
 drivers/firmware/dmi_scan.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

@@ -499,18 +499,19 @@ static int __init dmi_present(const u8 *
 	buf += 16;
 
 	if (memcmp(buf, "_DMI_", 5) == 0 && dmi_checksum(buf, 15)) {
+		if (smbios_ver)
+			dmi_ver = smbios_ver;
+		else
+			dmi_ver = (buf[14] & 0xF0) << 4 | (buf[14] & 0x0F);
 		dmi_num = get_unaligned_le16(buf + 12);
 		dmi_len = get_unaligned_le16(buf + 6);
 		dmi_base = get_unaligned_le32(buf + 8);
 
 		if (dmi_walk_early(dmi_decode) == 0) {
 			if (smbios_ver) {
-				dmi_ver = smbios_ver;
 				pr_info("SMBIOS %d.%d present.\n",
 				       dmi_ver >> 8, dmi_ver & 0xFF);
 			} else {
-				dmi_ver = (buf[14] & 0xF0) << 4 |
-					   (buf[14] & 0x0F);
 				pr_info("Legacy DMI %d.%d present.\n",
 				       dmi_ver >> 8, dmi_ver & 0xFF);
 			}

Patches currently in stable-queue which might be from [email protected] are

queue-4.0/hwmon-tmp401-do-not-auto-detect-chip-on-i2c-address-0x37.patch queue-4.0/firmware-dmi_scan-fix-ordering-of-product_uuid.patch queue-4.0/hwmon-nct6775-add-missing-sysfs-attribute-initialization.patch queue-4.0/hwmon-nct6683-add-missing-sysfs-attribute-initialization.patch