From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 93A1447F775 for ; Thu, 6 Aug 2026 22:02:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786053772; cv=none; b=FR/Q9RfbgB6BlVPJdUfdbN8GJ6f0XETs+TEVmM7Z0vWDTxCwxoVxgNpB1yW4bD+Xl8PHZmRD6yuG70KFr/Kpf41Q0sDWwjAP2o8COMXJGsR1cMg65f4lCtNxIPnouDgeYxajULS2pcDeRSYIOiiNwTttfzeLw0luGNUW6yChRQs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786053772; c=relaxed/simple; bh=mDdbtml7+73YD/CDn2hk4PckPDu7YKsZcizcRJfdvAQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jFblbQTIr7NhpDFMlbnWdq1u//zIXnBW7QtDrqdqae397qiJVE+qmTRpTTM9gq64FG5G/WuWrNCMyUuyEkVFm78zfKxLJh1SSkryWOnLC+qMQIo5zN2djQ0qpjZFdqz1NtyC9Stea6NME/vNUSnMc+YdQzRFX1I2LEq0Q4dmdUM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OgXIIl47; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OgXIIl47" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 754991F000E9; Thu, 6 Aug 2026 22:02:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786053771; bh=uGlv+jrGOZ6XQPQ0TpPxjxsxbjcpATLks9Mr4h9hu8U=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=OgXIIl47cL8jCbmjiT2oPxSfDMRAYoI0Mq1fyodW66HpIG5lXpHLeFDgC/J5lWVBk xlHC7BgVCaiw4lvevYpcVvm2rzGDZ7d+UhhAtvOKjIMsvUoMAJnDwOsN2IdBxaImwD LLNnlmCl2R/bAzY7afAMW7M1Az2AgDPsFtYGnzFp3h001j0FB24o6MjIRtEico6FqP nmhuewoVaXrURDYrv75kcpI17Ow2qjTIM7xm7qcoIJ/ZQ/1XCQtUC87RhFTwvtJm6A /PY91sYSvmPzybO4tWcLLQCtPjys5l16n3xjhZcGkAKjo5zSXelC2+3MzQTiiR0E5l +mGal0lcIjUZg== Date: Fri, 7 Aug 2026 00:02:47 +0200 From: Alejandro Colomar To: DJ Delorie Cc: linux-man@vger.kernel.org Subject: Re: [PATCH v5 2/4] man/man5/tunables.conf: Document system-wide tunables config Message-ID: References: Precedence: bulk X-Mailing-List: linux-man@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hyuzpqoqu7hn7pls" Content-Disposition: inline In-Reply-To: --hyuzpqoqu7hn7pls Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: DJ Delorie Cc: linux-man@vger.kernel.org Subject: Re: [PATCH v5 2/4] man/man5/tunables.conf: Document system-wide tunables config Message-ID: References: MIME-Version: 1.0 In-Reply-To: Hi DJ, > Date: 2026-08-06 16:44:30-0400 > From: DJ Delorie > >=20 > --- You forgot to sign. > man/man5/tunables.conf.5 | 145 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 145 insertions(+) > create mode 100644 man/man5/tunables.conf.5 >=20 > diff --git a/man/man5/tunables.conf.5 b/man/man5/tunables.conf.5 > new file mode 100644 > index 000000000..29beeb8f8 > --- /dev/null > +++ b/man/man5/tunables.conf.5 > @@ -0,0 +1,145 @@ > +.TH tunables.conf 5 (date) "Linux man-pages (unreleased)" > +.SH NAME > +tunables.conf \- tunables configuration file > +.SH SYNOPSIS > +.nf > +.B /etc/tunables.conf > +.fi > +.SH DESCRIPTION > +Tunables are a feature in the GNU C Library > +that allows application authors and distribution maintainers > +to alter the runtime library behavior to match their workload. > +For a list of supported tunables, > +please consult the glibc manual > +that corresponds to your installed version of glibc, > +or run the following command: > +.P > +.in +4n > +.EX > +ld.so \-\-list\-tunables > +.EE > +.P > +The file is parsed by > +.BR \%ldconfig (8) > +and the results stored in > +.IR /etc/ld.so.cache . > +The resulting data is read when a new process is created by > +.IR ld.so . Sorry for noticing this in v4; I forgot about it. I see this unresolved issue from earlier versions remains. ld.so(8) runs when a new program is executed --execve(2)--, not when a new process is created --fork(2)--, AFAIK. alx@devuan:~$ MANWIDTH=3D64 man fork | grep ld.so alx@devuan:~$ MANWIDTH=3D64 man execve | grep -C2 ld.so If the executable is an a.out dynamically linked binary executable containing shared=E2=80=90library stubs, the Linux dy=E2= =80=90 namic linker ld.so(8) is called at the start of execution to bring needed shared objects into memory and link the executable with them. -- ptrace(2), exec(3), fexecve(3), getauxval(3), getopt(3), system(3), capabilities(7), credentials(7), environ(7), path_resolution(7), ld.so(8) Linux man=E2=80=90pages 6.18=E2=80=9018... 2026=E2=80=9002=E2=80=9008 = execve(2) > +.P > +Each line in the file > +.I /etc/tunables.conf > +specifies a tunable, > +which is specified with a string of the form > +.IB name =3D value \f[R].\f[] > +.P > +The syntax allows lines to start with the keyword > +.I include s/I/B/ (since it's a literal, not a variable) Have a lovely night! Alex > +followed by a > +.BR \%glob (7) > +pattern. > +Files matching that pattern will be processed > +as if their contents were included at that point. > +.P > +Each line may include zero or more keywords or symbols at the beginning, > +which affect how each tunable affects each processes. > +The keywords must be separated by whitespace, > +but the symbols need not be. > +.TP > +.B overridable > +.TQ > +.B + > +Allow the tunable to be overridden by the > +.B GLIBC_TUNABLES > +environment variable when the process runs > +(this is the default). > +.TP > +.B nonoverridable > +.TQ > +.B \- > +Do not allow the tunable to be overridden by the environment variable. > +.TP > +.B onlysecure > +.TQ > +.B @ > +The tunable applies only to > +.B AT_SECURE > +processes, > +such as one started from a set-user-ID program, > +or one with elevated capabilities. > +.TP > +.B nonsecure > +.TQ > +.B $ > +The tunable applies only to > +.RB non- AT_SECURE > +processes (this is the default). > +.TP > +.B anysecure > +.TQ > +.B * > +The tunable applies to both > +.B AT_SECURE > +and > +.RB non- AT_SECURE > +processes. > +.P > +The file may also contain > +.IR filters , > +which limit the tunables following it. > +The effects of a filter are terminated by > +any of the following: > +.IP \[bu] 3 > +The end of the file. > +.PD 0 > +.IP \[bu] > +The end of an included file. > +.IP \[bu] > +An > +.B include > +directive. > +.IP \[bu] > +A new (possibly empty) filter. > +.PD > +.P > +The syntax is: > +.P > +.in +4n > +.EX > +.BI [ filter : pattern ] > +.EE > +.in > +.TP > +.B proc > +The > +.B proc > +filter limits the following tunables to processes > +whose name matches the pattern. > +The pattern may be an absolute path > +or just the base name. > +.P > +A filter can also be empty: > +.BR [] . > +Such a filter has no effects. > +.SH FILES > +.TP > +.I /etc/tunables.conf > +.TP > +.I /etc/ld.so.cache > +cached copy of tunables > +.SH EXAMPLES > +Example configuration file: > +.P > +.in +4n > +.EX > +glibc.malloc.arenas_max=3D5 > +onlysecure glibc.malloc.arenas_max=3D1 > +\-glibc.pthread.rseq=3D1 > +[proc:/bin/bad.program] > +\-glibc.pthread.rseq=3D0 > +[proc:some.program] > +\-glibc.malloc.mmap_threshold=3D65536 > +.EE > +.in > +.SH SEE ALSO > +.BR ld.so (8), > +.BR ldconfig (8) > --=20 > 2.47.3 --=20 --hyuzpqoqu7hn7pls Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmp1BIEACgkQ64mZXMKQ wqmjAQ/+PRHpheeJAbEylyfzg2/v1rWUiaK08+uLjmXEMNsvw8rN1NbgGH22ABDH YJZVpvgjY+LdUysJ3bhC09rteNq4+8850GAt9C5MAirI8WpvrZdXE2uvFXpEiwd7 bGI++dW9/In1Cpa8qkf61teYQPIkV7tOAFzSkBUFfiPDz1+H2akLwVYHTYrvpzbM ysKle8K1pR7Y4kqMw+dhLl84AnTkNA3bn8rZWggoOSNxpUhkNMwdRvjqLwfeu7Ho WiF4+9GdL3PbkjrgqVVVWqFOJQNIH+MrGYE1P2iPZghtA1wk2e3nvSELbXoQUdrF T4RAK1OqygXQAqVToTGdAMCTzaOGsdpx5eBXmB8bN7Sw/SkRUUlD0yXdxDaIchbM 9/RSXY8uXF8B5cWOPN4MZeaiH2W1jcW26/bAwA7X/hoYdZ/ilAzTmtj4U9bV6f+m y17fiU7aRxbxMHUC/GCIeX5Sz5Af8t7A5pbKlUIOKTATRxmbcRWmPCmYmere4UMG DmdlV/e6JJgL4/8+vzf6RsK55gR5ehjYTbha0T0z6EvJRHk3Jv69r6hX1v67Ncc6 2vhW4ggmh3egFFX70o//3H1MlzZ4Qd6JRtnwuiVmfMRrN0AAN+ZwKGjVoUa7de5k 73VdQ/ajJH063nQpm3tVNclDptu+tgxoCHpwGQlqsmg0IaiWJUY= =UCB5 -----END PGP SIGNATURE----- --hyuzpqoqu7hn7pls--