Message-ID: <205c33e6-0ec3-4ab3-8700-e02f95e15199@iki.fi>
Date: Wed, 3 Jul 2024 16:25:18 +0300
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Subject: Re: Refactoring backend fork+exec code
To: Thomas Munro <thomas.munro@gmail.com>,
 Nathan Bossart <nathandbossart@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>,
 reid.thompson@crunchydata.com, Robert Haas <robertmhaas@gmail.com>,
 Andres Freund <andres@anarazel.de>, Tristan Partin <tristan@neon.tech>
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From: Heikki Linnakangas <hlinnaka@iki.fi>
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On 18/05/2024 08:24, Thomas Munro wrote:
> Nitpicking from UBSan with EXEC_BACKEND on Linux (line numbers may be
> a bit off, from a branch of mine):
> 
> ../src/backend/postmaster/launch_backend.c:772:2: runtime error: null
> pointer passed as argument 2, which is declared to never be null
> ==13303==Using libbacktrace symbolizer.
>      #0 0x5555564b0202 in save_backend_variables
> ../src/backend/postmaster/launch_backend.c:772
>      #1 0x5555564b0242 in internal_forkexec
> ../src/backend/postmaster/launch_backend.c:311
>      #2 0x5555564b0bdd in postmaster_child_launch
> ../src/backend/postmaster/launch_backend.c:244
>      #3 0x5555564b3121 in StartChildProcess
> ../src/backend/postmaster/postmaster.c:3928
>      #4 0x5555564b933a in PostmasterMain
> ../src/backend/postmaster/postmaster.c:1357
>      #5 0x5555562de4ad in main ../src/backend/main/main.c:197
>      #6 0x7ffff667ad09 in __libc_start_main
> (/lib/x86_64-linux-gnu/libc.so.6+0x23d09)
>      #7 0x555555e34279 in _start
> (/tmp/cirrus-ci-build/build/tmp_install/usr/local/pgsql/bin/postgres+0x8e0279)
> 
> This silences it:
> 
> -       memcpy(param->startup_data, startup_data, startup_data_len);
> +       if (startup_data_len > 0)
> +               memcpy(param->startup_data, startup_data, startup_data_len);

Fixed, thanks!

On 17/06/2024 21:36, Nathan Bossart wrote:
> While looking into [0], I noticed that main() still only checks for the
> --fork prefix, but IIUC commit aafc05d removed all --fork* options except
> for --forkchild.  I've attached a patch to strengthen the check in main().
> This is definitely just a nitpick.

Fixed this too, thanks!

-- 
Heikki Linnakangas
Neon (https://neon.tech)