Re: [arch-general] Keyboard issue with kernel 4.15.5 (possible Arch issue?)

[Ralf Mardorf]

As a real-time audio user, too, be sure, I'm as well using a PS/2
keyboard. A PS/2 keyboard should work. However, from time to time it
could happen, that the keyboard's lock LEDs start blinking during
startup and startup doesn't finish, but the messages don't show a
kernel panic or something keyboard related. If this happens, I just
need to reset the computer, a second startup always worked for me.
assuming your keyboard should be broken, they still sell brand new
native PS/2 keyboards in all price ranges. Due to the USB keyboard
issues PS/2 keyboards are seemingly much more important to gamers, than
for real-time audio users.

Btw. "core" provides 4.15.8. I already upgraded to 4.15.8 early Monday
morning and FWIW I skipped 4.15.5 and upgraded from 4.15.4-1 to
4.15.6-1, so I don't know if something is fishy with 4.15.5.

pacman -Q linux{,-rt{,-securityink,-pussytoes,-cornflower}}|cut -d\  -f2
4.15.8-1
4.14.24_rt19-1
4.14.20_rt17-1
4.14.8_rt9-2
4.11.12_rt16-1

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[David C. Rankin]

On 03/13/2018 03:28 PM, mar77i via arch-general wrote:
> On 03/13/2018 02:17 AM, PkmX via arch-general wrote:
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607
> 
> Pass -std=... to compiling the programi n question. If it's in clear 
> deviation of what the respective standard dictates, it's a bug.
> 
> 
> ​Sent with ProtonMail Secure Email.​
> 

Yes, confirmed it was indeed a bug:

  $ gcc -Wall -Wextra -pedantic -std=c11 -o bin/infunc2 infunc2.c
  $ ./bin/infunc2
  In main

And, with Jelle van der Waa's suggestion, I loaded clang (which I never
otherwise install) and it confirms the issue further:

  $ clang -Wall -Wextra -pedantic -std=c11 -o infunc2 infunc2.c
  $ ./infunc2
  In func
  In main

The only part I'm unclear on is where in the fix process
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607 is on getting fixed and
when that will trickle down to us.

-- 
David C. Rankin, J.D.,P.E.

Re: [arch-general] Xorg crashes

[Jagannathan Tiruvallur Eachambadi via arch-general]

On Tuesday 13 March 2018 12:53:10 PM CET Thomas Dreher wrote:
> Libinput is broken. Downgrading to 1.10.1-1 works.

Can you link any bug report regarding this. I am running into the same issue 
and it has irritating to see even X crash since it has been stable for a long 
time.
-- 
Kind regards
Jagan

signature.asc
Description: This is a digitally signed message part.

Re: [arch-general] Keyboard issue with kernel 4.15.5 (possible Arch issue?)

[Jeanette C. via arch-general]

Mar 13 2018, Carsten Mattner has written:
...

Does the keyboard function in BIOS?

Can't tell, I'm blind and there's no screen connected anyway. Don't have
one anymore.


Does it work if boot another distro's live usb or cd?

Hm, I should really try that. Thanks for the hint.


You said 4.13/4.14 before so I don't think you're affected by the
initramfs changes in 2014:

https://www.archlinux.org/news/linux-313-warning-ps2-keyboard-support-is-now-modular/

Shouldn't be.
...

Best wishes and thanks,

Jeanette


 * Website: http://juliencoder.de - for summer is a state of sound
 * SoundCloud: https://soundcloud.com/jeanette_c
 * GitHub: https://github.com/fsilvain
 * Twitter: https://twitter.com/ffanci_silvain

All I need is time
A moment that is mine
While I'm in between <3
(Britney Spears)

Re: [arch-general] Keyboard issue with kernel 4.15.5 (possible Arch issue?)

[Carsten Mattner via arch-general]

On 3/13/18, Jeanette C. via arch-general  wrote:
> Hey hey,
> I updated yesterday, from some;thing like a 4.13 or 4.14 kernel to version
> 4.15.5 and couldn't use my PS/2 keyboard. I saw the LEDs flashing when the
> system started, but couldn't get any response from the keyboard upon login.
>
> I've managed to get the system going with a USB keyboard.
>
> My PS/2 keyboard is rather old. Is it more likely that the keyboard is
> broken, or is there a chance of a kernel configuration breaking usage of
> the PS/2 keyboard?

Does the keyboard function in BIOS?

Does it work if boot another distro's live usb or cd?

You said 4.13/4.14 before so I don't think you're affected by the
initramfs changes in 2014:

https://www.archlinux.org/news/linux-313-warning-ps2-keyboard-support-is-now-modular/

[arch-general] Keyboard issue with kernel 4.15.5 (possible Arch issue?)

[Jeanette C. via arch-general]

Hey hey,
I updated yesterday, from some;thing like a 4.13 or 4.14 kernel to version 
4.15.5 and couldn't use my PS/2 keyboard. I saw the LEDs flashing when the 
system started, but couldn't get any response from the keyboard upon login. 
I've managed to get the system going with a USB keyboard.


My PS/2 keyboard is rather old. Is it more likely that the keyboard is broken, 
or is there a chance of a kernel configuration breaking usage of the PS/2 
keyboard?


Best wishes,

Jeanette


 * Website: http://juliencoder.de - for summer is a state of sound
 * SoundCloud: https://soundcloud.com/jeanette_c
 * GitHub: https://github.com/fsilvain
 * Twitter: https://twitter.com/ffanci_silvain

All I need is time
A moment that is mine
While I'm in between <3
(Britney Spears)

Re: [arch-general] Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting

[Carsten Mattner via arch-general]

On 3/13/18, Eli Schwartz via arch-general  wrote:

> Like I said, this can be done from any system which has pacman and
> mkinitcpio available. That means:
>
> 1) Arch Linux
> 2) Gentoo, which has a pacman package and IIRC also provides mkinitcpio
>as an option alongside dracut.
> 3) Any Linux distribution if you have chrooted into the bootstrap image
> 4) Windows (or any operating system, really), by using a virtual machine
>
> Certainly, anything is *possible* if you put in enough work. But making
> something annoyingly difficult to do is, as I said, hardly a generic
> solution.

True and Alpine Linux supports (3.5) ZFS on install which I didn't confirm
because, like I said, I don't use ZFS on Linux. I mean that if Arch
ZFS developers want to, they can leverage work from other distros.
I guess it's a good thing Arch has no installer or otherwise there
might be a heated debate whether ZFS should be an option :).

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[mar77i via arch-general]

On 03/13/2018 02:17 AM, PkmX via arch-general wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607

Pass -std=... to compiling the programi n question. If it's in clear deviation 
of what the respective standard dictates, it's a bug.


​Sent with ProtonMail Secure Email.​

Re: [arch-general] Xorg crashes

[Peter Nabbefeld]

Thank You! So, as I'm not an experienced linux dev (not even C++ or 
Python), I'll probably never be able to. However, IMHO problems with 
Xorg input should probably be mentioned ...


Kind regards
Peter


Am 13.03.2018 um 15:56 schrieb Eli Schwartz via arch-general:

On 03/13/2018 07:59 AM, Peter Nabbefeld wrote:

Am 13.03.2018 um 12:53 schrieb Thomas Dreher:

Am Dienstag, 13. März 2018, 11:58:08 CET schrieb Peter Nabbefeld:

Hello all,

since yesterday, Xorg sometimes crashes unexpectedly. Please, see log
below.

Libinput is broken. Downgrading to 1.10.1-1 works.


Thank You, Thomas!  :)

There's a feed for those problems ("Arch Linux Recent news updates") -
how can this be added there?

By becoming an Arch dev and deciding it qualifies as news.

Re: [arch-general] Xorg crashes

[Eli Schwartz via arch-general]

On 03/13/2018 07:59 AM, Peter Nabbefeld wrote:
> Am 13.03.2018 um 12:53 schrieb Thomas Dreher:
>> Am Dienstag, 13. März 2018, 11:58:08 CET schrieb Peter Nabbefeld:
>>> Hello all,
>>>
>>> since yesterday, Xorg sometimes crashes unexpectedly. Please, see log
>>> below.
>>
>> Libinput is broken. Downgrading to 1.10.1-1 works.
>>
> 
> Thank You, Thomas!  :)
> 
> There's a feed for those problems ("Arch Linux Recent news updates") -
> how can this be added there?

By becoming an Arch dev and deciding it qualifies as news.

-- 
Eli Schwartz
Bug Wrangler and Trusted User



signature.asc
Description: OpenPGP digital signature

Re: [arch-general] Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting

[Eli Schwartz via arch-general]

On 03/13/2018 09:47 AM, Leonid Isaev via arch-general wrote:
> On Tue, Mar 13, 2018 at 09:41:46AM -0400, Eli Schwartz via arch-general wrote:
>> On 03/13/2018 12:30 AM, John Ramsden via arch-general wrote:
>>> Actually, you can easily create an arch ISO with ZFS embedded into
>>> it. It's what I do, and it takes about five minutes to create.
>>>
>>> https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
>>
>> Yes, and it also requires an Arch system (or at least one with pacman
>> available) to run mkarchiso, pacstrap, copy the initcpio configs from
>> mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
>> don't really consider this a viable generic solution...
> 
> Can't this be done from any distro using Arch rootfs?

Like I said, this can be done from any system which has pacman and
mkinitcpio available. That means:

1) Arch Linux
2) Gentoo, which has a pacman package and IIRC also provides mkinitcpio
   as an option alongside dracut.
3) Any Linux distribution if you have chrooted into the bootstrap image
4) Windows (or any operating system, really), by using a virtual machine

Certainly, anything is *possible* if you put in enough work. But making
something annoyingly difficult to do is, as I said, hardly a generic
solution.

-- 
Eli Schwartz
Bug Wrangler and Trusted User



signature.asc
Description: OpenPGP digital signature

Re: [arch-general] Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting

[Leonid Isaev via arch-general]

On Tue, Mar 13, 2018 at 09:41:46AM -0400, Eli Schwartz via arch-general wrote:
> On 03/13/2018 12:30 AM, John Ramsden via arch-general wrote:
> > Actually, you can easily create an arch ISO with ZFS embedded into
> > it. It's what I do, and it takes about five minutes to create.
> > 
> > https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html
> 
> Yes, and it also requires an Arch system (or at least one with pacman
> available) to run mkarchiso, pacstrap, copy the initcpio configs from
> mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
> don't really consider this a viable generic solution...

Can't this be done from any distro using Arch rootfs?

Cheers,
-- 
Leonid Isaev

Re: [arch-general] Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting

[Eli Schwartz via arch-general]

On 03/13/2018 12:30 AM, John Ramsden via arch-general wrote:
> Actually, you can easily create an arch ISO with ZFS embedded into
> it. It's what I do, and it takes about five minutes to create.
> 
> https://ramsdenj.com/2016/06/23/arch-linux-on-zfs-part-1-embed-zfs-in-archiso.html

Yes, and it also requires an Arch system (or at least one with pacman
available) to run mkarchiso, pacstrap, copy the initcpio configs from
mkinitcpio, etc. Which is a bit of a chicken-and-egg problem, and I
don't really consider this a viable generic solution...

-- 
Eli Schwartz
Bug Wrangler and Trusted User



signature.asc
Description: OpenPGP digital signature

Re: [arch-general] High CPU on one core, but unable to find process responsible

[David Rosenstrauch]

On 03/13/2018 03:34 AM, Carsten Mattner via arch-general wrote:

On 3/13/18, David Rosenstrauch  wrote >> I have an old PCI 
card in the machine that's powers an old parallel port

printer I used to use with it.  Perhaps that's failing.  I don't need
the card anymore, so I might as well try taking it out and see if that
makes things better.  If not, I'll be back.  :-)


Let us know in either case. Please tell me it's a huge plotter
you use to make construction plans for your rocket ships.



Just an old printer that's been good to me that I've been reluctant to 
let go of:


https://www.cnet.com/products/hp-laserjet-6l/specs/

DR

Re: [arch-general] Xorg crashes

[Peter Nabbefeld]

Am 13.03.2018 um 12:53 schrieb Thomas Dreher:

Am Dienstag, 13. März 2018, 11:58:08 CET schrieb Peter Nabbefeld:

Hello all,

since yesterday, Xorg sometimes crashes unexpectedly. Please, see log below.


Libinput is broken. Downgrading to 1.10.1-1 works.



Thank You, Thomas!  :)

There's a feed for those problems ("Arch Linux Recent news updates") - 
how can this be added there?


Regards
Peter

Re: [arch-general] Xorg crashes

[Thomas Dreher]

Am Dienstag, 13. März 2018, 11:58:08 CET schrieb Peter Nabbefeld:
> Hello all,
> 
> since yesterday, Xorg sometimes crashes unexpectedly. Please, see log below.

Libinput is broken. Downgrading to 1.10.1-1 works.

[arch-general] Xorg crashes

[Peter Nabbefeld]

Hello all,

since yesterday, Xorg sometimes crashes unexpectedly. Please, see log below.

I'm not sure, but I'm using Firefox most time, and Xorg crashes while 
I'm using Firefox.


I'm no expert, but on a first glance, it seems to me like my touchpad 
accumulates mouse movements and so the input device gives the wrong 
coordinates to FF which in turn hands them to Xorg which leads to 
crashes. But of course, I may be totally wrong with this assumption.


Kind regards
Peter


[   213.002]
X.Org X Server 1.19.6
Release Date: 2017-12-20
[   213.002] X Protocol Version 11, Revision 0
[   213.002] Build Operating System: Linux 4.14.12-1-ARCH x86_64
[   213.002] Current Operating System: Linux tuchola 4.15.8-1-ARCH #1
SMP PREEMPT Sat Mar 10 00:00:33 UTC 2018 x86_64
[   213.002] Kernel command line: BOOT_IMAGE=/vmlinuz-linux
root=UUID=e81ed24f-26ef-4220-832a-56c374907fb0 rw quiet
rcutree.rcu_idle_gp_delay=1
[   213.002] Build Date: 26 January 2018  10:25:18AM
[   213.002]
[   213.002] Current version of pixman: 0.34.0
[   213.002]Before reporting problems, check http://wiki.x.org
to make sure that you have the latest version.
[   213.002] Markers: (--) probed, (**) from config file, (==) default
setting,
(++) from command line, (!!) notice, (II) informational,
(WW) warning, (EE) error, (NI) not implemented, (??) unknown.
[   213.003] (==) Log file: "/home/peter/.local/share/xorg/Xorg.0.log",
Time: Mon Mar 12 14:49:32 2018
[   213.076] (==) Using config directory: "/etc/X11/xorg.conf.d"
[   213.076] (==) Using system config directory "/usr/share/X11/xorg.conf.d"
[   213.146] (==) No Layout section.  Using the first Screen section.
[   213.146] (==) No screen section available. Using defaults.
[   213.146] (**) |-->Screen "Default Screen Section" (0)
[   213.146] (**) |   |-->Monitor ""
[   213.168] (==) No device specified for screen "Default Screen Section".
Using the first device section listed.
[   213.168] (**) |   |-->Device "Intel Graphics"
[   213.168] (**) |   |-->GPUDevice "Nvidia card"
[   213.168] (==) No monitor specified for screen "Default Screen Section".
Using a default monitor configuration.
[   213.168] (==) Automatically adding devices
[   213.168] (==) Automatically enabling devices
[   213.168] (==) Automatically adding GPU devices
[   213.168] (==) Automatically binding GPU devices
[   213.168] (==) Max clients allowed: 256, resource mask: 0x1f
[   213.222] (WW) `fonts.dir' not found (or not valid) in
"/usr/share/fonts/100dpi/".
[   213.222]Entry deleted from font path.
[   213.222](Run 'mkfontdir' on "/usr/share/fonts/100dpi/").
[   213.222] (WW) `fonts.dir' not found (or not valid) in
"/usr/share/fonts/75dpi/".
[   213.222]Entry deleted from font path.
[   213.222](Run 'mkfontdir' on "/usr/share/fonts/75dpi/").
[   213.222] (==) FontPath set to:
/usr/share/fonts/misc/,
/usr/share/fonts/TTF/,
/usr/share/fonts/OTF/,
/usr/share/fonts/Type1/
[   213.222] (==) ModulePath set to "/usr/lib/xorg/modules"
[   213.222] (II) The server relies on udev to provide the list of input
devices.
If no devices become available, reconfigure udev or disable 
AutoAddDevices.
[   213.222] (II) Loader magic: 0x55ed101fbd60
[   213.222] (II) Module ABI versions:
[   213.222]X.Org ANSI C Emulation: 0.4
[   213.222]X.Org Video Driver: 23.0
[   213.222]X.Org XInput driver : 24.1
[   213.222]X.Org Server Extension : 10.0
[   213.223] (++) using VT number 1

[   213.223] (--) controlling tty is VT number 1, auto-enabling KeepTty
[   213.224] (II) systemd-logind: took control of session
/org/freedesktop/login1/session/c1
[   213.225] (II) xfree86: Adding drm device (/dev/dri/card1)
[   213.225] (II) systemd-logind: got fd for /dev/dri/card1 226:1 fd 11
paused 0
[   213.226] (II) xfree86: Adding drm device (/dev/dri/card0)
[   213.226] (II) systemd-logind: got fd for /dev/dri/card0 226:0 fd 12
paused 0
[   213.228] (--) PCI:*(0:0:2:0) 8086:0416:1558:7481 rev 6, Mem @
0xf740/4194304, 0xd000/268435456, I/O @ 0xf000/64, BIOS @
0x/131072
[   213.228] (--) PCI: (0:1:0:0) 10de:119a:1558:7481 rev 161, Mem @
0xf600/16777216, 0xe000/268435456, 0xf000/33554432, I/O @
0xe000/128, BIOS @ 0x/524288
[   213.228] (II) Open ACPI successful (/var/run/acpid.socket)
[   213.228] (II) LoadModule: "glx"
[   213.247] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so
[   213.298] (II) Module glx: vendor="X.Org Foundation"
[   213.298]compiled for 1.19.6, module version = 1.0.0
[   213.298]ABI class: X.Org Server Extension, version 10.0
[   213.298] (II) LoadModule: "intel"
[   213.298] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so
[   213.325] (II) Module intel: vendor="X.Org Foundation"
[   213.325]compiled for 1.19.6, module version = 2.99.917
[   213.325]Module class: X.Org Video Driver
[   213.325]ABI class: X.Org Video Driver, version 23.0

Re: [arch-general] Update to 4.15.8 on dual quad-core box locked on ( 3/16) Install DKMS modules, need help resurecting

[Kyle Bassett via arch-general]

Hi Carsten, I'm glad you ended up posting this to the list.  Very useful
info, even if I never end up using it.

The rest of this thread has some great content too.

Thanks all!



On Mar 11, 2018 21:03, "Carsten Mattner via arch-general" <
arch-general@archlinux.org> wrote:

> On 3/11/18, David C. Rankin  wrote:
>
> > This was a nightmare. It's not a CD problem, it's a problem with the
> system
> > seeing the CD Label and/or creating the /dev/disk/by-label directory in
> > time for the link to be created.
>
> Hi David,
>
> so in the end you were able to boot off usb, right?
>
> Also, the nightmare you had to work through can be avoided on servers
> where you run illumos or FreeBSD by way of ZFS boot environments (BE).
> Basically, it's like Windows style snapshots of core files you can
> boot, in case stuff goes south.
>
> I didn't post this to the list, since it mentions ZFS, and that alone
> might get some people pissed off.
>

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[David C. Rankin]

On 03/13/2018 02:17 AM, PkmX via arch-general wrote:
> Hi,
> 
> AFAIK this is the exact case of gcc bugzilla #84607:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607
> 
> As this is an upstream bug this should affect all distributions, maybe
> the commenter on Debian is using 7.3.1 so he can't reproduce the
> issue?
> 

That is good to know that it is being addressed. I can see this current
handling of optimizations causing many of subtle non-traceable and just plain
"wonky" errors that have been see these past few days. I thought the guy who
posted it was nuts... It built and had the correct output on SuSE, but when I
tried it on Arch - WTF? they was right. Who knows in how many subtle ways that
could manifest itself. I've convinced it is as the root of the (Out of IOMMU
space) error I have in the logs, and more than likely it is responsible for my
hardlocks on the big servers. We will be looking for a fix -- hopefully soon.

Thank you for letting me know.

-- 
David C. Rankin, J.D.,P.E.

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[Jelle van der Waa]

On 03/13/18 at 03:17pm, PkmX via arch-general wrote:
> Hi,
> 
> AFAIK this is the exact case of gcc bugzilla #84607:
> 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607
> 
> As this is an upstream bug this should affect all distributions, maybe
> the commenter on Debian is using 7.3.1 so he can't reproduce the
> issue?
> 

BTW, cross checking with clang was also an option :-)

[jelle@starfighter][/tmp]%clang foo.c
[jelle@starfighter][/tmp]%./a.out
In func
In main

Feel free to make a bugreport on https://bugs.archlinux.org


signature.asc
Description: PGP signature

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[Carsten Mattner via arch-general]

On 3/13/18, PkmX via arch-general  wrote:
> Hi,
>
> AFAIK this is the exact case of gcc bugzilla #84607:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607
>
> As this is an upstream bug this should affect all distributions, maybe
> the commenter on Debian is using 7.3.1 so he can't reproduce the
> issue?

Let's not forget that Debian is patch happy (as is Ubuntu, logically),
especially for gcc. Mostly for good reason but quite a bit is too
many diffs:

https://sources.debian.org/src/gcc-7/7.3.0-11/debian/patches/

It's quite possible that the snapshot plus diffs fixes/hides the bug
on Debian. Fedora is another distro that is very happy to carry
many diffs for some packages. Thinks of the version string like
git-gc-7.3.1+dirty in mainstream distros. It's like a downstream
branch.

Re: [arch-general] High CPU on one core, but unable to find process responsible

[Carsten Mattner via arch-general]

On 3/13/18, David Rosenstrauch  wrote:
>
>
> On 03/12/2018 09:56 PM, Carsten Mattner via arch-general wrote:
>> Any BIOS updates or kernel updates recently (4.15.8)?
>>
>> Try with 3.16 or 4.9 or another old lts kernel from archive.archlinux.org
>> just for testing (not production).
>>
>> It's more likely that the kernel regressed rather than IRQ issues popping
>> up suddenly. It's possible but less likely.
>
> No BIOS updates.  As far as kernel updates, I do those all the time, so
> not sure that would be the cause.
>
> After doing some digging, though, I did "cat /proc/interrupts", and this
> line stood out, for having an astronomically high number:
>
> CPU0   CPU1   CPU2   CPU3
> ...
>   16: 2424156658  0  0  0   IO-APIC  16-fasteoi
>   uhci_hcd:usb5, parport1
>
>
> I have an old PCI card in the machine that's powers an old parallel port
> printer I used to use with it.  Perhaps that's failing.  I don't need
> the card anymore, so I might as well try taking it out and see if that
> makes things better.  If not, I'll be back.  :-)

Let us know in either case. Please tell me it's a huge plotter
you use to make construction plans for your rocket ships.

Re: [arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[PkmX via arch-general]

Hi,

AFAIK this is the exact case of gcc bugzilla #84607:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607

As this is an upstream bug this should affect all distributions, maybe
the commenter on Debian is using 7.3.1 so he can't reproduce the
issue?

On Tue, Mar 13, 2018 at 2:36 PM, David C. Rankin
 wrote:
> Houston -- we have a problem.
>
>   The problem is gcc is mis-applying optimizations, and it seems Arch
> specific. See discussion:
>
> [Why does not execute printf inside function?]
> https://stackoverflow.com/questions/49248787/why-does-not-execute-printf-inside-function/49249533#49249533
>
>   The basic issue can be summarized in this short snippet:
>
> #include 
>
> int arr[10];
>
> int func()
> {
> printf ("In func\n");
> return 0;
> }
>
> int main (void)
> {
> if ([func()])
> printf("In main\n");
> return 0;
> }
>
>   Compile (with or without optimization) and the output on Archlinux (all
> packages current as of 1hr ago) and you get:
>
> $ ./bin/if2
> In main
>
>   That is wrong. `func()` has been completely optimized out of the procedure
> in main(). The assembly generated omits any call to func. (full assembly
> posted as part of the answer on SO)
>
>   Debian gcc 7.3 does not exhibit this same behavior. I do not know where to
> start looking to find why this is happening, but it does not take much of a
> stretch to see how this could be the root cause of some of the "unexplained"
> errors I and others have seen in the past few days on Arch.
>
>   Let me know if I need to file a bug here. Since it "works on Debian" and not
> here, I suspect the bug should start here and so the default optimization we
> package with can be eliminated.
>
>   What say the devs?
>
>
> --
> David C. Rankin, J.D.,P.E.

[arch-general] gcc broken - Arch specific, applying optimization incorrectly - may explain unexplained problems

[David C. Rankin]

Houston -- we have a problem.

  The problem is gcc is mis-applying optimizations, and it seems Arch
specific. See discussion:

[Why does not execute printf inside function?]
https://stackoverflow.com/questions/49248787/why-does-not-execute-printf-inside-function/49249533#49249533

  The basic issue can be summarized in this short snippet:

#include 

int arr[10];

int func()
{
printf ("In func\n");
return 0;
}

int main (void)
{
if ([func()])
printf("In main\n");
return 0;
}

  Compile (with or without optimization) and the output on Archlinux (all
packages current as of 1hr ago) and you get:

$ ./bin/if2
In main

  That is wrong. `func()` has been completely optimized out of the procedure
in main(). The assembly generated omits any call to func. (full assembly
posted as part of the answer on SO)

  Debian gcc 7.3 does not exhibit this same behavior. I do not know where to
start looking to find why this is happening, but it does not take much of a
stretch to see how this could be the root cause of some of the "unexplained"
errors I and others have seen in the past few days on Arch.

  Let me know if I need to file a bug here. Since it "works on Debian" and not
here, I suspect the bug should start here and so the default optimization we
package with can be eliminated.

  What say the devs?


-- 
David C. Rankin, J.D.,P.E.