From nobody Sat Feb 7 07:43:06 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA4E3C4332F for ; Tue, 12 Dec 2023 10:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232073AbjLLKMq (ORCPT ); Tue, 12 Dec 2023 05:12:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235042AbjLLKMj (ORCPT ); Tue, 12 Dec 2023 05:12:39 -0500 Received: from tarta.nabijaczleweli.xyz (tarta.nabijaczleweli.xyz [139.28.40.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC15C10B; Tue, 12 Dec 2023 02:12:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=nabijaczleweli.xyz; s=202305; t=1702375963; bh=Lx01uUzZBLjfFlGQlKARFoT+Vf/QEeNIG29aSuy6Lf8=; h=Date:From:To:Subject:References:In-Reply-To:From; b=OT4OnGfpCidozTgeKJqlenrtbf0JerI1R/jU8yP204BjK4j3qeUs4ZqZNwq+f6H// wKV4HqXL7mYXXFJBLq2OKLvweJzrd2nRxE/rO5JGD4Ud/xGcZeyQuVEh6jmP1Udhog F1sTysJ+py9xrbtTHlxfK1QRFaZU0qzUB2Zj4tlnMrRM/ceBvOATJsNlsbAVtek1xP ouydr8agHAM56ic655re4rEW/1CWxSZE2nbSX6g89ldVK3ux4shwpRzDKF+qQVtqQd ph+hT5GDTBF728he4SOcBE2bdo9J9iPxtaP3Xf5qRpwFLPN20bh99gPmenALHXd0Oz N1dY4hhdd8a4Q== Received: from tarta.nabijaczleweli.xyz (unknown [192.168.1.250]) by tarta.nabijaczleweli.xyz (Postfix) with ESMTPSA id 0700D12A7C; Tue, 12 Dec 2023 11:12:43 +0100 (CET) Date: Tue, 12 Dec 2023 11:12:42 +0100 From: Ahelenia =?utf-8?Q?Ziemia=C5=84ska?= To: Steven Rostedt , Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH RESEND 04/11] tracing: tracing_buffers_splice_read: behave as-if non-blocking I/O Message-ID: <11b84f2e4e5eaad501ff7b2bb03e2ad2f25ecdf14.1697486714.git.nabijaczleweli@nabijaczleweli.xyz> User-Agent: NeoMutt/20231103 References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hv3lx7g2ikvzxdyu" Content-Disposition: inline In-Reply-To: <1cover.1697486714.git.nabijaczleweli@nabijaczleweli.xyz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --hv3lx7g2ikvzxdyu Content-Disposition: inline Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Otherwise we risk sleeping with the pipe locked for indeterminate lengths of time. Link: https://lore.kernel.org/linux-fsdevel/qk6hjuam54khlaikf2ssom6custxf5i= s2ekkaequf4hvode3ls@zgf7j5j4ubvw/t/#u Signed-off-by: Ahelenia Ziemia=C5=84ska --- kernel/trace/trace.c | 32 ++++---------------------------- 1 file changed, 4 insertions(+), 28 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index abaaf516fcae..9be7a4c0a3ca 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8477,7 +8477,6 @@ tracing_buffers_splice_read(struct file *file, loff_t= *ppos, if (splice_grow_spd(pipe, &spd)) return -ENOMEM; =20 - again: trace_access_lock(iter->cpu_file); entries =3D ring_buffer_entries_cpu(iter->array_buffer->buffer, iter->cpu= _file); =20 @@ -8528,35 +8527,12 @@ tracing_buffers_splice_read(struct file *file, loff= _t *ppos, =20 /* did we read anything? */ if (!spd.nr_pages) { - long wait_index; - - if (ret) - goto out; - - ret =3D -EAGAIN; - if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) - goto out; - - wait_index =3D READ_ONCE(iter->wait_index); - - ret =3D wait_on_pipe(iter, iter->tr->buffer_percent); - if (ret) - goto out; - - /* No need to wait after waking up when tracing is off */ - if (!tracer_tracing_is_on(iter->tr)) - goto out; - - /* Make sure we see the new wait_index */ - smp_rmb(); - if (wait_index !=3D iter->wait_index) - goto out; - - goto again; + if (!ret) + ret =3D -EAGAIN; + } else { + ret =3D splice_to_pipe(pipe, &spd); } =20 - ret =3D splice_to_pipe(pipe, &spd); -out: splice_shrink_spd(&spd); =20 return ret; --=20 2.39.2 --hv3lx7g2ikvzxdyu Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfWlHToQCjFzAxEFjvP0LAY0mWPEFAmV4MhoACgkQvP0LAY0m WPEQ4w/+LmJ9g+sTLdWI+2h/NDpBO07CFF47oOhsehFB7o3yH8UophMOzrOdxYZQ NYzzY+11ga72QE+rwRD3yLxdbQfZzDE2PUNT4eJdgAXA/3hsKqkw4VbuTN4tlrPP 5MTyjKC3GX5LjeBO32neK8SYUhZkabu108eflv+8XcpE32cW22gGuA71YcajuDj1 3Y9jblVjAT8acO0Zec6ZHOB6ZYBggwMMYyA0M+Me16sqxmBR1JToqNLeZkSh2Nfn 1IR1tzixc82NRPkFDYormthq5PEg3w/VIj0yvCEDRJKU1DqPrmYRBxahOe3JjKMI 54oQTopZEFK7vR9m0Vv31wmeXjw4da15elHNYE9FJj24URAJuCqMsHObwyt2BRmp GOwcWPL89TVL4sN/lywa5Vb0A+DqxwCT0mfdrbhzAtwiBfnWbFCe3znyA+Jzcvwi ube6KYote7bsLxDbbogcptP0RoL5+++cWissl4jGp2taZntQ6YWwx1P7qEyyKKvO GZ94AXF4Vy159bJYlVdMp1JHzibVtC0XkRlzgrmU976HE0ycbz4eW5/Bjc7lYJqh H0hlrwy8yUL6nnAjEfq6FEXo/rFJg5/s8ocWOMxHw/z+qUgv2+vP1bmt896AeL94 lCjPfm9DK0AA9/8wzdStv8q26yvVepmBROjWiQhsaGM4Vplx7Uk= =KLoG -----END PGP SIGNATURE----- --hv3lx7g2ikvzxdyu--