[edk2-devel] [PATCH v2 1/2] MdeModulePkg/Bus/Pci/UhciDxe: Fix BAD_SHIFT Coverity issue

["Ranbir Singh" <rsingh@ventanamicro.com>]

From: Ranbir Singh <Ranbir.Singh3@Dell.com>

The function UhciConvertPollRate has a check

    ASSERT (Interval != 0);

but this comes into play only in DEBUG mode. In Release mode, there is
no handling if the Interval parameter value is ZERO. To avoid shifting
by a negative amount later in the code flow in this undesirable case,
it is better to handle it as well by treating it same as if 1 is sent.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4211

Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Co-authored-by: Veeresh Sangolli <veeresh.sangolli@dellteam.com>
Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
---
 MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c b/MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c
index c08f9496969b..408e7d5ab7f3 100644
--- a/MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c
+++ b/MdeModulePkg/Bus/Pci/UhciDxe/UhciSched.c
@@ -197,7 +197,7 @@ UhciDestoryFrameList (
 }
 
 /**
-  Convert the poll rate to the maxium 2^n that is smaller
+  Convert the poll rate to the maximum 2^n that is smaller
   than Interval.
 
   @param  Interval               The poll rate to convert.
@@ -214,6 +214,14 @@ UhciConvertPollRate (
 
   ASSERT (Interval != 0);
 
+  //
+  // To safeguard RELEASE mode wherein ASSERT is effectively not there,
+  // if inadvertently Interval is still 0 here, treat it the same as 1.
+  //
+  if (Interval == 0) {
+    Interval = 1;
+  }
+
   //
   // Find the index (1 based) of the highest non-zero bit
   //
-- 
2.34.1



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