Sorry for the triple post; I received a bounce email the first time and got sent to the spam folder the second time, so I'm trying a third time.
Hello, all. I was running Mesa with Address Sanitizer [1] turned on, and found one place where ASAN pointed out a read-before-initialized problem. In particular, in _mesa_add_parameter, in prog_parameter.c, |values| represents an array holding a variable number of values. These values get copied out of the array 4 at a time with the COPY_4V macro, however, the array might only contain a single element. In this case, ASAN reports a read-before-initialize because the last 3 of the 4 elements haven't been written to yet. I was hoping to contribute a patch that will silence this problem that ASAN reports. I'm happy to incorporate any feedback anyone has into this patch. Thanks, Myles C. Maxfield [1] https://code.google.com/p/address-sanitizer/ diff --git a/src/mesa/program/prog_parameter.c b/src/mesa/program/prog_parameter.c index 2018fa5..63915fb 100644 --- a/src/mesa/program/prog_parameter.c +++ b/src/mesa/program/prog_parameter.c @@ -158,7 +158,17 @@ _mesa_add_parameter(struct gl_program_parameter_list *paramList, p->DataType = datatype; p->Flags = flags; if (values) { - COPY_4V(paramList->ParameterValues[oldNum + i], values); + if (size & 3) { + for (j = 0; j < size; j++) { + paramList->ParameterValues[oldNum + i][j] = values[j]; + } + /* silence asan */ + for (j = size; j < 4; j++) { + paramList->ParameterValues[oldNum + i][j].f = 0; + } + } else { + COPY_4V(paramList->ParameterValues[oldNum + i], values); + } values += 4; p->Initialized = GL_TRUE; }
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