Pushed via:
PR - https://github.com/tianocore/edk2/pull/2399
Commit -
https://github.com/tianocore/edk2/commit/6062002bd5a394fef46243dd866860c3480d918e
Best Regards,
Hao Wu
From: devel@edk2.groups.io <devel@edk2.groups.io>
On Behalf Of Wu, Hao A
Sent: Thursday, January 6, 2022 11:21 AM
To: Edwards, Craig <Craig.Edwards@dell.com>; Gao, Liming <gaoliming@byosoft.com.cn>; Wang, Jian J <jian.j.wang@intel.com>; Ni, Ray <ray.ni@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>; devel@edk2.groups.io; Shutt, Mark <mark.shutt@dell.com>
Subject: Re: [edk2-devel] [Patch MBR endless loop hang with invalid LBA0 1/1] MdeModulePkg/PartitionDxe: Add break to handle invalid LBA0 in MBR
Inline comment below:
From: Edwards, Craig <Craig.Edwards@dell.com>
Sent: Thursday, January 6, 2022 2:53 AM
To: Gao, Liming <gaoliming@byosoft.com.cn>; Wang, Jian J <jian.j.wang@intel.com>; Wu, Hao A <hao.a.wu@intel.com>; Ni, Ray
<ray.ni@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>;
devel@edk2.groups.io; Shutt, Mark <mark.shutt@dell.com>
Subject: [Patch MBR endless loop hang with invalid LBA0 1/1] MdeModulePkg/PartitionDxe: Add break to handle invalid LBA0 in MBR
Read Disk does a modification of ExtMbrStartingLba with the code MultU64x32
(ExtMbrStartingLba, BlockSize) Error detection to see if ExtMbrStartingLBA
has a value of 0. This is invalid as LBA 0 = MBR. After modification, the
next time ExtMbrStartingLba is in this function if ExtMbrStartingLba is set
to 0 in the MBR it never passes the while/do evaluation It is multiplied by 0
by read disk , set to 0 by an invalid MBR and goes back to evaluation This
condition will also cause Ws19 and WS22 to hang, however Microsoft has
developed a hotfix patch that will be released in 2022
Cc:
Liming Gao <gaoliming@byosoft.com.cn>
Cc:
Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc:
Ray Ni <ray.ni@intel.com>
Cc:
Zhichao Gao <zhichao.gao@intel.com>
Signed-off-by: Craig Edwards <craig.edwards@dell.com>
Date: Wed Jan 5 12:27:46 2022 -0600
On branch graceful_handle_mbr_hang_edit1
Changes to be committed:
modified: MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
---
MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
index 0f8dc5486521..ad18840e5efd 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
@@ -293,6 +293,12 @@ PartitionInstallMbrChildHandles (
(Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION))
{
ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);
+ //
+ // A value of 0 is invalid for StartingLBA
+ //
+ if (ExtMbrStartingLba == 0) {
+ break;
+ }
Seems the indent includes 2 unneeded spaces. I will help to remove them when merging the patch.
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
Will wait a couple of days before merging to see if comments from other reviewers.
Best Regards,
Hao Wu
continue;
}
--
2.32.0.windows.1
Craig Edwards
Software Engineer
Dell | GDP | PSE | COMMS | BIOS