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Date:   Tue, 31 Oct 2023 11:40:48 -0400
From:   Paul Gortmaker <paul.gortmaker@windriver.com>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Richard Purdie <richard.purdie@linuxfoundation.org>,
        Borislav Petkov <bp@alien8.de>, x86@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: 32 bit qemu regression from v6.5 tip pull [6c480f222128
 x86/alternative: Rewrite optimize_nops() some]
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[Re: 32 bit qemu regression from v6.5 tip pull [6c480f222128 x86/alternative: Rewrite optimize_nops() some]] On 30/10/2023 (Mon 20:30) Thomas Gleixner wrote:

> On Mon, Oct 30 2023 at 19:24, Thomas Gleixner wrote:

> > Can you add "debug-alternative" to the kernel command line and log both
> > a working and the non-working kernel output. It's noisy :)
> >
> > Also do you have a .config and the qemu command line handy?
> 
> Forgot to ask: Does the probkem persist with 6.6 ?

My bad, should have mentioned v6.6 and linux-next is impacted. Always a
conflict between burying the lead and boring people with details.

The "debug-alternative" is definitely "chatty" -- the "works" case is
easy to capture -- working on getting a snapshot of the "fails" case.

I will attach a .config to the yocto bugzilla case, for lack of a better
place to put it.

The giant sh*tshow of qemu args used by QA are as follows:

Running
paul/poky/build-qemu-x86_32/tmp/work/x86_64-linux/qemu-helper-native/1.0/recipe-sysroot-native/usr/bin/qemu-system-i386 
-device virtio-net-pci,netdev=net0,mac=52:54:00:12:34:02 -netdev
tap,id=net0,ifname=tap0,script=no,downscript=no -object
rng-random,filename=/dev/urandom,id=r
ng0 -device virtio-rng-pci,rng=rng0 -drive
file=./core-image-minimal-qemux86.rootfs.ext4.2545136,if=virtio,format=raw
-usb -device usb-tablet -usb -device usb
-kbd   -cpu IvyBridge -machine q35,i8042=off -smp 4 -m 256 -serial
tcp:127.0.0.1:45019 -serial tcp:127.0.0.1:49567  -pidfile
/folk/pgortmak/tglx/pidfile_25451
32  -S -qmp unix:./.ut8nuyx1,server,wait -qmp
unix:./.7mu5pxk1,server,nowait -nographic  -kernel
/yow-lpggp32/paul/poky/build-qemu-x86_32/tmp/deploy/images/qemux86/bzImage -append 'root=/dev/vda rw
ip=192.168.7.2::192.168.7.1:255.255.255.0::eth0:off:8.8.8.8
net.ifnames=0 console=ttyS0 console=ttyS1 oprofile.timer=
1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1 swiotlb=0
debug-alternative printk.time=1'

It pains me that it fills a screen.  But there it is.