RH covscan emits the following false positive:
> Error: CLANG_WARNING:
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:182:14:
> warning: Dereference of undefined pointer value
> # Status = FwVol->ReadSection (
> # ^~~~~~~~~~~~~~~~~~
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:164:7: note:
> Assuming the condition is false
> # if (QemuDetected ()) {
> # ^~~~~~~~~~~~~~~
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:164:3: note:
> Taking false branch
> # if (QemuDetected ()) {
> # ^
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:174:3: note:
> Taking false branch
> # if (EFI_ERROR (Status)) {
> # ^
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:180:10: note:
> Assuming 'Status' is equal to EFI_SUCCESS
> # while (Status == EFI_SUCCESS) {
> # ^~~~~~~~~~~~~~~~~~~~~
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:180:3: note:
> Loop condition is true. Entering loop body
> # while (Status == EFI_SUCCESS) {
> # ^
> edk2-
89910a39dcfd/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c:182:14: note:
> Dereference of undefined pointer value
> # Status = FwVol->ReadSection (
> # ^~~~~~~~~~~~~~~~~~
> # 180| while (Status == EFI_SUCCESS) {
> # 181|
> # 182|-> Status = FwVol->ReadSection (
> # 183| FwVol,
> # 184| (EFI_GUID*)PcdGetPtr (PcdAcpiTableStorageFile),
This is invalid because LocateFvInstanceWithTables() sets FwVol on
success.
Suppress the message by:
- assigning FwVol NULL first (this would replace the original report with
"nullptr deref"),
- asserting that FwVol is no longer NULL, on success.
What's important here is that ASSERT() ends with ANALYZER_UNREACHABLE() on
failure.
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1710
Issue: scan-0991.txt
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>