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

> On 14 Mar 2025, at 08:58, PG Bug reporting form <noreply@postgresql.org> wrote:
> 
> The following bug has been logged on the website:
> 
> Bug reference:      18845
> Logged by:          Nikita
> Email address:      pm91.arapov@gmail.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