Re: BUG #18845: DEREF_OF_NULL.RET guc_malloc possibly returns NULL

> On 14 Mar 2025, at 08:58, PG Bug reporting form <noreply(at)postgresql(dot)org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference: 18845
> Logged by: Nikita
> Email address: pm91(dot)arapov(at)gmail(dot)com
> PostgreSQL version: 16.6
> Operating system: ubuntu 20.04
> Description:
>
> guc_malloc possibly returns NULL, if no memory
> I suggest the following patch fixing this issue
>
> diff --git a/src/backend/commands/user.c b/src/backend/commands/user.c
> --- a/src/backend/commands/user.c (revision
> a49ac80219c6f28c3cf3973f797de637329952da)
> +++ b/src/backend/commands/user.c (date 1740386879158)
> @@ -2553,7 +2553,7 @@
> pfree(rawstring);
> list_free(elemlist);
>
> - result = (unsigned *) guc_malloc(LOG, sizeof(unsigned));
> + result = (unsigned *) guc_malloc(FATAL, sizeof(unsigned));

Why would we want FATAL here? Wouldn't it be better to return false like how
other check_ functions already do?

--- a/src/backend/commands/user.c
+++ b/src/backend/commands/user.c
@@ -2566,6 +2566,8 @@ check_createrole_self_grant(char **newval, void **extra, GucSource source)
list_free(elemlist);

result = (unsigned *) guc_malloc(LOG, sizeof(unsigned));
+ if (!result)
+ return false;
*result = options;
*extra = result;

--
Daniel Gustafsson