alsa-devel.alsa-project.org archive mirror
 help / color / mirror / Atom feed
From: Jakub Kicinski <kuba@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: alsa-devel@alsa-project.org,
	linux-atm-general@lists.sourceforge.net,
	reiserfs-devel@vger.kernel.org, linux-iio@vger.kernel.org,
	linux-wireless@vger.kernel.org, linux-fbdev@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Nathan Chancellor <natechancellor@gmail.com>,
	linux-ide@vger.kernel.org, dm-devel@redhat.com,
	keyrings@vger.kernel.org, linux-mtd@lists.infradead.org,
	GR-everest-linux-l2@marvell.com, wcn36xx@lists.infradead.org,
	samba-technical@lists.samba.org, linux-i3c@lists.infradead.org,
	linux1394-devel@lists.sourceforge.net,
	linux-afs@lists.infradead.org,
	usb-storage@lists.one-eyed-alien.net, drbd-dev@lists.linbit.com,
	devel@driverdev.osuosl.org, linux-cifs@vger.kernel.org,
	rds-devel@oss.oracle.com,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org,
	oss-drivers@netronome.com, bridge@lists.linux-foundation.org,
	linux-security-module@vger.kernel.org,
	amd-gfx@lists.freedesktop.org,
	linux-stm32@st-md-mailman.stormreply.com,
	cluster-devel@redhat.com, linux-acpi@vger.kernel.org,
	coreteam@netfilter.org, intel-wired-lan@lists.osuosl.org,
	linux-input@vger.kernel.org, Miguel Ojeda <ojeda@kernel.org>,
	tipc-discussion@lists.sourceforge.net,
	linux-ext4@vger.kernel.org, linux-media@vger.kernel.org,
	linux-watchdog@vger.kernel.org, selinux@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	linux-geode@lists.infradead.org, linux-can@vger.kernel.org,
	linux-block@vger.kernel.org, linux-gpio@vger.kernel.org,
	op-tee@lists.trustedfirmware.org,
	linux-mediatek@lists.infradead.org,
	xen-devel@lists.xenproject.org, nouveau@lists.freedesktop.org,
	linux-hams@vger.kernel.org, ceph-devel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org,
	linux-hwmon@vger.kernel.org, x86@kernel.org,
	linux-nfs@vger.kernel.org, GR-Linux-NIC-Dev@marvell.com,
	linux-mm@kvack.org, netdev@vger.kernel.org,
	linux-decnet-user@lists.sourceforge.net,
	linux-mmc@vger.kernel.org,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	linux-renesas-soc@vger.kernel.org, linux-sctp@vger.kernel.org,
	linux-usb@vger.kernel.org, netfilter-devel@vger.kernel.org,
	linux-crypto@vger.kernel.org, patches@opensource.cirrus.com,
	Joe Perches <joe@perches.com>,
	linux-integrity@vger.kernel.org, target-devel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: Re: [PATCH 000/141] Fix fall-through warnings for Clang
Date: Fri, 20 Nov 2020 11:51:42 -0800	[thread overview]
Message-ID: <20201120115142.292999b2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <202011201129.B13FDB3C@keescook>

On Fri, 20 Nov 2020 11:30:40 -0800 Kees Cook wrote:
> On Fri, Nov 20, 2020 at 10:53:44AM -0800, Jakub Kicinski wrote:
> > On Fri, 20 Nov 2020 12:21:39 -0600 Gustavo A. R. Silva wrote:  
> > > This series aims to fix almost all remaining fall-through warnings in
> > > order to enable -Wimplicit-fallthrough for Clang.
> > > 
> > > In preparation to enable -Wimplicit-fallthrough for Clang, explicitly
> > > add multiple break/goto/return/fallthrough statements instead of just
> > > letting the code fall through to the next case.
> > > 
> > > Notice that in order to enable -Wimplicit-fallthrough for Clang, this
> > > change[1] is meant to be reverted at some point. So, this patch helps
> > > to move in that direction.
> > > 
> > > Something important to mention is that there is currently a discrepancy
> > > between GCC and Clang when dealing with switch fall-through to empty case
> > > statements or to cases that only contain a break/continue/return
> > > statement[2][3][4].  
> > 
> > Are we sure we want to make this change? Was it discussed before?
> > 
> > Are there any bugs Clangs puritanical definition of fallthrough helped
> > find?
> > 
> > IMVHO compiler warnings are supposed to warn about issues that could
> > be bugs. Falling through to default: break; can hardly be a bug?!  
> 
> It's certainly a place where the intent is not always clear. I think
> this makes all the cases unambiguous, and doesn't impact the machine
> code, since the compiler will happily optimize away any behavioral
> redundancy.

If none of the 140 patches here fix a real bug, and there is no change
to machine code then it sounds to me like a W=2 kind of a warning.

I think clang is just being annoying here, but if I'm the only one who
feels this way chances are I'm wrong :)

  reply	other threads:[~2020-11-24 17:01 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-20 18:21 [PATCH 000/141] Fix fall-through warnings for Clang Gustavo A. R. Silva
2020-11-20 18:23 ` [PATCH 002/141] ASoC: codecs: " Gustavo A. R. Silva
2020-11-20 18:28 ` [PATCH 000/141] " Joe Perches
2020-11-20 19:02   ` Gustavo A. R. Silva
2020-11-20 18:33 ` [PATCH 066/141] ALSA: hdspm: " Gustavo A. R. Silva
2020-11-21  8:30   ` Takashi Iwai
2020-11-23 22:56     ` Gustavo A. R. Silva
2020-11-20 18:34 ` [PATCH 067/141] ALSA: pcsp: " Gustavo A. R. Silva
2020-11-21  8:30   ` Takashi Iwai
2020-11-20 18:34 ` [PATCH 068/141] ALSA: sb: " Gustavo A. R. Silva
2020-11-21  8:29   ` Takashi Iwai
2020-11-20 18:39 ` [PATCH 126/141] slimbus: messaging: " Gustavo A. R. Silva
2020-11-24 10:48   ` Srinivas Kandagatla
2020-11-24 14:38     ` Gustavo A. R. Silva
2020-11-20 18:53 ` [PATCH 000/141] " Jakub Kicinski
2020-11-20 19:04   ` Gustavo A. R. Silva
2020-11-20 19:30   ` Kees Cook
2020-11-20 19:51     ` Jakub Kicinski [this message]
2020-11-20 20:48       ` Kees Cook
2020-11-22 16:17       ` Kees Cook
2020-11-22 18:21         ` James Bottomley
2020-11-22 18:25           ` Joe Perches
2020-11-22 19:12             ` James Bottomley
2020-11-22 19:22               ` Joe Perches
2020-11-22 19:53                 ` James Bottomley
2020-11-23 13:03                   ` [Intel-wired-lan] " Gustavo A. R. Silva
2020-11-23 16:31                     ` James Bottomley
2020-11-22 20:35           ` Miguel Ojeda
2020-11-22 22:36             ` James Bottomley
2020-11-23 14:19               ` Miguel Ojeda
2020-11-23 15:58                 ` James Bottomley
2020-11-23 16:24                   ` Rafael J. Wysocki
2020-11-23 16:32                   ` Joe Perches
2020-11-23 18:56                   ` Miguel Ojeda
2020-11-23 20:37                     ` James Bottomley
     [not found]                       ` <CANiq72kqO=bYMJnFS2uYRpgWATJ=uXxZuNUsTXT+3aLtrpnzvQ@mail.gmail.com>
     [not found]                         ` <44005bde-f6d4-5eaa-39b8-1a5efeedb2d3@gmail.com>
2020-11-26 14:53                           ` Miguel Ojeda
2020-11-26 15:28                             ` Geert Uytterhoeven
2020-11-26 16:18                               ` Karol Herbst
2020-11-26 17:05                               ` Miguel Ojeda
2020-11-22 22:54             ` Finn Thain
2020-11-22 23:04               ` James Bottomley
2020-11-23 14:05               ` Miguel Ojeda
2020-11-24  0:58                 ` Finn Thain
2020-11-24  1:05                   ` Joe Perches
2020-11-24  2:48                     ` Finn Thain
2020-11-22 22:10           ` Sam Ravnborg
2020-11-24  1:32         ` Nick Desaulniers
2020-11-24  1:46           ` Jakub Kicinski
2020-12-01 14:08           ` Dan Carpenter
2020-12-01 14:04         ` Dan Carpenter
2020-11-20 22:21 ` Miguel Ojeda
2020-11-23 20:03 ` Jason Gunthorpe
2020-11-24 14:47   ` Gustavo A. R. Silva
2020-11-23 20:38 ` Mark Brown
2020-11-24 14:47   ` Gustavo A. R. Silva
     [not found] ` <yq1h7p6gjkk.fsf@ca-mkp.ca.oracle.com>
2020-12-01  8:20   ` Gustavo A. R. Silva
2020-12-08  4:52 ` (subset) " Martin K. Petersen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201120115142.292999b2@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com \
    --to=kuba@kernel.org \
    --cc=GR-Linux-NIC-Dev@marvell.com \
    --cc=GR-everest-linux-l2@marvell.com \
    --cc=alsa-devel@alsa-project.org \
    --cc=amd-gfx@lists.freedesktop.org \
    --cc=bridge@lists.linux-foundation.org \
    --cc=ceph-devel@vger.kernel.org \
    --cc=cluster-devel@redhat.com \
    --cc=coreteam@netfilter.org \
    --cc=devel@driverdev.osuosl.org \
    --cc=dm-devel@redhat.com \
    --cc=drbd-dev@lists.linbit.com \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=gustavoars@kernel.org \
    --cc=intel-gfx@lists.freedesktop.org \
    --cc=intel-wired-lan@lists.osuosl.org \
    --cc=joe@perches.com \
    --cc=keescook@chromium.org \
    --cc=keyrings@vger.kernel.org \
    --cc=linux-acpi@vger.kernel.org \
    --cc=linux-afs@lists.infradead.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-atm-general@lists.sourceforge.net \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-can@vger.kernel.org \
    --cc=linux-cifs@vger.kernel.org \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-decnet-user@lists.sourceforge.net \
    --cc=linux-ext4@vger.kernel.org \
    --cc=linux-fbdev@vger.kernel.org \
    --cc=linux-geode@lists.infradead.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-hams@vger.kernel.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-hwmon@vger.kernel.org \
    --cc=linux-i3c@lists.infradead.org \
    --cc=linux-ide@vger.kernel.org \
    --cc=linux-iio@vger.kernel.org \
    --cc=linux-input@vger.kernel.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-mmc@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=linux-nfs@vger.kernel.org \
    --cc=linux-rdma@vger.kernel.org \
    --cc=linux-renesas-soc@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=linux-sctp@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=linux-stm32@st-md-mailman.stormreply.com \
    --cc=linux-usb@vger.kernel.org \
    --cc=linux-watchdog@vger.kernel.org \
    --cc=linux-wireless@vger.kernel.org \
    --cc=linux1394-devel@lists.sourceforge.net \
    --cc=natechancellor@gmail.com \
    --cc=ndesaulniers@google.com \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    --cc=nouveau@lists.freedesktop.org \
    --cc=ojeda@kernel.org \
    --cc=op-tee@lists.trustedfirmware.org \
    --cc=oss-drivers@netronome.com \
    --cc=patches@opensource.cirrus.com \
    --cc=rds-devel@oss.oracle.com \
    --cc=reiserfs-devel@vger.kernel.org \
    --cc=samba-technical@lists.samba.org \
    --cc=selinux@vger.kernel.org \
    --cc=target-devel@vger.kernel.org \
    --cc=tipc-discussion@lists.sourceforge.net \
    --cc=usb-storage@lists.one-eyed-alien.net \
    --cc=virtualization@lists.linux-foundation.org \
    --cc=wcn36xx@lists.infradead.org \
    --cc=x86@kernel.org \
    --cc=xen-devel@lists.xenproject.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).