Re: [PATCH] inet/net-internal.h: Fix uninitalised clntudp_call() variable

[Alistair Francis <alistair23 at gmail dot com>]

On Mon, Sep 16, 2019 at 3:19 PM Alistair Francis
<alistair.francis@wdc.com> wrote:
>
> The total_deadline variable inside the clntudp_call() function inside
> sunrpc/clnt_udp.c can cause uninitalised variable warnings when building
> with GCC 8.3 or 9.2 on a platform with a 64-bit tv_nsec on a 32-bit
> architecture. To fix the warning let's use the DIAG_* macros to hide the
> warning.
>
> A GCC bug case has also been submitted:
>     https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91691
>
> 2019-09-16  Alistair Francis  <alistair.francis@wdc.com>
>
>         * inet/net-internal.h: Fix uninitalised clntudp_call() variable

Ping! Is this patch ok to go in?

Alistair

> ---
>  inet/net-internal.h | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/inet/net-internal.h b/inet/net-internal.h
> index 2f522eef555..c774de2b78a 100644
> --- a/inet/net-internal.h
> +++ b/inet/net-internal.h
> @@ -23,6 +23,7 @@
>  #include <stdbool.h>
>  #include <stdint.h>
>  #include <sys/time.h>
> +#include <libc-diag.h>
>
>  int __inet6_scopeid_pton (const struct in6_addr *address,
>                            const char *scope, uint32_t *result);
> @@ -96,6 +97,16 @@ __deadline_is_infinite (struct deadline deadline)
>    return deadline.absolute.tv_nsec < 0;
>  }
>
> +/* GCC 8.3 and 9.2 both incorrectly report total_deadline
> + * (from sunrpc/clnt_udp.c) as maybe-uninitialized when tv_sec is 8 bytes
> + * (64-bits) wide on 32-bit systems. We have to set -Wmaybe-uninitialized
> + * here as it won't fix the error in sunrpc/clnt_udp.c.
> + * A GCC bug has been filed here:
> + *    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91691
> + */
> +DIAG_PUSH_NEEDS_COMMENT;
> +DIAG_IGNORE_NEEDS_COMMENT (9, "-Wmaybe-uninitialized");
> +
>  /* Return true if the current time is at the deadline or past it.  */
>  static inline bool
>  __deadline_elapsed (struct deadline_current_time current,
> @@ -120,6 +131,8 @@ __deadline_first (struct deadline left, struct deadline right)
>      return right;
>  }
>
> +DIAG_POP_NEEDS_COMMENT;
> +
>  /* Add TV to the current time and return it.  Returns a special
>     infinite absolute deadline on overflow.  */
>  struct deadline __deadline_from_timeval (struct deadline_current_time,
> --
> 2.23.0
>