Re: [SeaBIOS] GCC 7.1 warning in `tcgbios.c`: `'hleo.eventnumber' may be used uninitialized in this function`

[Kevin O'Connor]

On Thu, Aug 10, 2017 at 08:52:06PM +0200, Paul Menzel wrote:
> Dear SeaBIOS folks,
>
> GCC 7.1 warns about a maybe uninitialized struct member.
> src/tcgbios.c: In function 'tpm_interrupt_handler32':
> src/tcgbios.c:1232:30: warning: 'hleo.eventnumber' may be used uninitialized
> in this function [-Wmaybe-uninitialized]
>      hleeo->eventnumber = hleo.eventnumber;
>                           ~~~~^~~~~~~~~~~~
>   Compiling whole program out/ccode32flat.o
> In file included from out/ccode32flat.o.tmp.c:52:0:
> ./src/tcgbios.c: In function 'tpm_interrupt_handler32':
> ./src/tcgbios.c:1232:30: warning: 'hleo.eventnumber' may be used
> uninitialized in this function [-Wmaybe-uninitialized]
>      hleeo->eventnumber = hleo.eventnumber;
>                           ~~~~^~~~~~~~~~~~
>
> It looks valid, as in the beginning the struct hleo is only declared.
> 1189     struct hleo hleo;

Agreed - the warning does look valid.  I think the patch below should
fix it.

-Kevin

--- a/src/tcgbios.c
+++ b/src/tcgbios.c
@@ -1186,7 +1186,6 @@ hash_log_extend_event_int(const struct hleei_short *hleei_s,
                           struct hleeo *hleeo)
 {
     u32 rc = 0;
-    struct hleo hleo;
     struct hleei_long *hleei_l = (struct hleei_long *)hleei_s;
     const void *logdataptr;
     u32 logdatalen;
@@ -1229,7 +1228,7 @@ hash_log_extend_event_int(const struct hleei_short *hleei_s,

hleeo->opblength = sizeof(struct hleeo);
     hleeo->reserved  = 0;
-    hleeo->eventnumber = hleo.eventnumber;
+    hleeo->eventnumber = tpm_state.entry_count;
     memcpy(hleeo->digest, pcpes->digest, sizeof(hleeo->digest));

err_exit: