From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 48A2F1A6826 for ; Wed, 18 Mar 2026 00:36:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773794173; cv=none; b=lD6hM6A7b/VXJKHiWbKB65hjPogW3sj3gSWdQH0sZOqnOPACcui3iZq7eROgbZuLh6ptDl/bA7H4zWtS/RMbwOgP8rFzIfz5m23j7SMS87Y4d8/umRMDgNtAmqMBxNs1wxrHy07s+GVCG9egS25HEPunht57knNKJa7Uex6NHyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773794173; c=relaxed/simple; bh=aSMJ8MHGgoQTa0379P0ji/JX75p9Jb1uh8A7aYB6LpU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=J6sh0NogZS5B0ueZ/WjI1nGqH7vWQ2pzXZFnzMi3Yd2HEs4vX2EbwpJ5Y/iZICNd9vhWRQKux9pJzYhkfpogGd3zWqKtWmTyj3UeYhNiR1whGGUOfXKaKJsDt+M71IXgRtF76WK9a33zNTCvsFTRMH5dVsj9OWY8AiAKY+vpl9g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aaMmDgfP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aaMmDgfP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DABEBC4CEF7; Wed, 18 Mar 2026 00:36:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773794172; bh=aSMJ8MHGgoQTa0379P0ji/JX75p9Jb1uh8A7aYB6LpU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aaMmDgfPNNrWVKJJEnAf190LBpx+wDBslS1AS4H6I72JiFVQrthAM+1Mv2CfRuh/X z17xUG467OGTtlwML7gs7RGwW3aemN3ixKl+lwAMunynlyCu72K8yCwmv+RhRAZwEo /tqXspsZVJT5iVewZoO00Z12L98sStpwaebHKXxVETiLGyBk6oLTpBGVE6+GDk5rLb B3jsHHHKPvHC3rer3lXpkbodVmhOsZyiZyh99MFPZT9jRllWLT+KcWKqP0CtX8rzzT 3veydhDKw1p8KWffzmL5tpJaszsg35kaHhq5EKPI6uBCtMPIj1nwwZ5El8Cqt6OXri NbBh1QSJK/u8g== Date: Wed, 18 Mar 2026 01:36:09 +0100 From: Alejandro Colomar To: Ben Kallus Cc: linux-man@vger.kernel.org Subject: Re: [PATCH] man/man2/mmap.2: Document that MAP_GROWSDOWN doesn't affect mmap return value. Message-ID: References: <20260317214652.2135374-1-benjamin.p.kallus.gr@dartmouth.edu> 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="ko2rxcwq4tvhoche" Content-Disposition: inline In-Reply-To: <20260317214652.2135374-1-benjamin.p.kallus.gr@dartmouth.edu> --ko2rxcwq4tvhoche Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable From: Alejandro Colomar To: Ben Kallus Cc: linux-man@vger.kernel.org Subject: Re: [PATCH] man/man2/mmap.2: Document that MAP_GROWSDOWN doesn't affect mmap return value. Message-ID: References: <20260317214652.2135374-1-benjamin.p.kallus.gr@dartmouth.edu> MIME-Version: 1.0 In-Reply-To: <20260317214652.2135374-1-benjamin.p.kallus.gr@dartmouth.edu> Hi Ben, > Subject: Re: [PATCH] man/man2/mmap.2: Document that MAP_GROWSDOWN > doesn't affect mmap return value. Please include patch version in the [] prefix. See . Also, please send In-Reply-To previous iterations. See And ideally, include a range-diff that compares the patch against the previous iteration. See . On 2026-03-17T17:46:52-0400, Ben Kallus wrote: > The man page states that the MAP_GROWSDOWN flag causes the kernel to retu= rn an > address one page lower than the mapping created. This is not true; the ke= rnel Please use two spaces after period. See . > returns the base address of the mapping created, just as it does when > MAP_GROWSDOWN is not passed. This can be confirmed by inspecting > /proc/self/maps after making a gd mapping, and comparing it to the return= ed > value from mmap. Please include in the commit message the example program you sent in the previous thread about this patch. > Fixes: 176b1a76 (2016-11-21; "mmap.2: Add (much) more detail on MAP_GROWS= DOWN") >=20 > Signed-off-by: Ben Kallus Please no blank lines between Fixes and SoB. The trailer should be a single block. Have a lovely night! Alex > --- > man/man2/mmap.2 | 2 -- > 1 file changed, 2 deletions(-) >=20 > diff --git a/man/man2/mmap.2 b/man/man2/mmap.2 > index 09e7933d3..20b94c243 100644 > --- a/man/man2/mmap.2 > +++ b/man/man2/mmap.2 > @@ -276,8 +276,6 @@ should check the returned address against the request= ed address. > This flag is used for stacks. > It indicates to the kernel virtual memory system that the mapping > should extend downward in memory. > -The return address is one page lower than the memory area that is > -actually created in the process's virtual address space. > Touching an address in the "guard" page below the mapping will cause > the mapping to grow by a page. > This growth can be repeated until the mapping grows to within a > --=20 > 2.53.0 >=20 >=20 --=20 --ko2rxcwq4tvhoche Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEES7Jt9u9GbmlWADAi64mZXMKQwqkFAmm583MACgkQ64mZXMKQ wqm5+hAAo4bDi3xwyXK4QF/vPPY8ehCwbHX6LXvjv/iEnuQD2AnpXoLheUiyLLWn rYShgbTxfe96BaOSQkpdFdXaLUTz56P99Z778QPm2SBH+KogmQdYgZ6ybsdnGR7C yKFNANFZtu/oMaHmmQI9dsycb8XwAH1gyRjVjvUIaDnOSYiLdOv5wD2EtV4S7YZo veD8TRazlaS8AR0FUeq0Kyw4Jshpjw5BzWGgIrAlwZtTOCdoEPkrAjxCd2OurJ1F vesNQAfGNX7wIdlCiiPvgZvcMHK/xEIPN/1fH2a+XKnl48dz6Zg+yV0zNIAb4Xs9 IcoCaQ2r/nZ8996agQVvRsHNJZeQmxWQkE+Ds+C53jZbtpQ1EMgIDAw7twQrDwLv b3EWrYRilV8Jebsvl1hXr0kbXqLQmkDnpgpo/CgPJ6HfO/gathn3+uQ7t5fPCQyv qwUEyb3+2pN2ChRSwAp09VfFgMGXJZIbo8fXV3Fa3RcG9/cbauYfvHZ5gXxLeUgp C5wvBFypR3+hBIbW8NIxupqkLPK4mRa/sbvKutr52GGMzSVFJeKrw9xhemSJgZJr zRx0lYsYm4Gz1vJli0RfE8SArI6MGg8hRimYQ6NqFc7UIzSo92Jf54HSK74/NqYC oY3K7Wcq7JdHnZ/5jEwJG9gPRIQyxm3FM9Gj3H+WrHz0m3evT74= =/EAO -----END PGP SIGNATURE----- --ko2rxcwq4tvhoche--