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<p class="MsoNormal">Inline comment below:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> Edwards, Craig <Craig.Edwards@dell.com> <br>
<b>Sent:</b> Thursday, January 6, 2022 2:53 AM<br>
<b>To:</b> 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><br>
<b>Subject:</b> [Patch MBR endless loop hang with invalid LBA0 1/1] MdeModulePkg/PartitionDxe: Add break to handle invalid LBA0 in MBR<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">Read Disk does a modification of ExtMbrStartingLba with the code MultU64x32<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">(ExtMbrStartingLba, BlockSize) Error detection to see if ExtMbrStartingLBA<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">has a value of 0. This is invalid as LBA 0 = MBR. After modification, the<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">next time ExtMbrStartingLba is in this function if ExtMbrStartingLba is set<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">to 0 in the MBR it never passes the while/do evaluation It is multiplied by 0<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">by read disk , set to 0 by an invalid MBR and goes back to evaluation This<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">condition will also cause Ws19 and WS22 to hang, however Microsoft has<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">developed a hotfix patch that will be released in 2022<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> <o:p></o:p></span></p>
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<p class="MsoNormal">Cc: <span style="font-size:9.0pt;font-family:"Lucida Console"">
Liming Gao</span> <<a href="mailto:gaoliming@byosoft.com.cn"><span style="font-size:9.0pt;font-family:"Lucida Console";color:#0563C1">gaoliming@byosoft.com.cn</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal">Cc: <span style="font-size:9.0pt;font-family:"Lucida Console"">
Jian J Wang</span> <<a href="mailto:jian.j.wang@intel.com"><span style="font-size:9.0pt;font-family:"Lucida Console";color:#0563C1">jian.j.wang@intel.com</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal">Cc: Hao A Wu <<a href="mailto:hao.a.wu@intel.com"><span style="color:#0563C1">hao.a.wu@intel.com</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal">Cc: <span style="font-size:9.0pt;font-family:"Lucida Console"">
Ray Ni</span> <<a href="mailto:ray.ni@intel.com"><span style="font-size:9.0pt;font-family:"Lucida Console";color:#0563C1">ray.ni@intel.com</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal">Cc: <span style="font-size:9.0pt;font-family:"Lucida Console"">
Zhichao Gao</span> <<a href="mailto:zhichao.gao@intel.com"><span style="font-size:9.0pt;font-family:"Lucida Console";color:#0563C1">zhichao.gao@intel.com</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"> <span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal">Signed-off-by: Craig Edwards <<a href="mailto:craig.edwards@dell.com"><span style="color:#0563C1">craig.edwards@dell.com</span></a>><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"> <span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">Date: Wed Jan 5 12:27:46 2022 -0600<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">On branch graceful_handle_mbr_hang_edit1<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">Changes to be committed:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> modified: MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">---<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c | 6 ++++++<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">1 file changed, 6 insertions(+)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">index 0f8dc5486521..ad18840e5efd 100644<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">@@ -293,6 +293,12 @@ PartitionInstallMbrChildHandles (<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> (Mbr->Partition[0].OSIndicator == EXTENDED_WINDOWS_PARTITION))<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> {<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> ExtMbrStartingLba = UNPACK_UINT32 (Mbr->Partition[0].StartingLBA);<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ //<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ // A value of 0 is invalid for StartingLBA<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ //<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ if (ExtMbrStartingLba == 0) {<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ break;<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">+ }<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Seems the indent includes 2 unneeded spaces. I will help to remove them when merging the patch.<o:p></o:p></p>
<p class="MsoNormal">Reviewed-by: Hao A Wu <hao.a.wu@intel.com><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Will wait a couple of days before merging to see if comments from other reviewers.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best Regards,<o:p></o:p></p>
<p class="MsoNormal">Hao Wu<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> continue;<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console""> }<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">--<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Lucida Console"">2.32.0.windows.1<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Craig Edwards</span></b><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#1F497D">Software Engineer
</span><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#007CB9">Dell</span></b><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#1F497D"> | GDP | PSE | COMMS | BIOS</span><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"><a href="mailto:Craig_Edwards@Dell.com%0d"><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:#0563C1">Craig_Edwards@Dell.com</span></a><span style="font-size:9.0pt;font-family:"Lucida Console""><o:p></o:p></span></p>
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<p class="MsoNormal"><br>
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