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Date:   Wed, 14 Jun 2023 13:20:11 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Richard W.M. Jones" <rjones@redhat.com>
Cc:     Aaron Thompson <dev@aaront.org>, linux-kernel@vger.kernel.org
Subject: Re: printk.time causes rare kernel boot hangs
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On Wed, Jun 14, 2023 at 11:30:11AM +0100, Richard W.M. Jones wrote:
> OK I have a simpler test:
> 
> $ while true; do qemu-system-x86_64 -no-user-config -nodefaults -display none -machine accel=kvm:tcg,graphics=off -cpu max,la57=off -m 1280 -no-reboot -rtc driftfix=slew -no-hpet -global kvm-pit.lost_tick_policy=discard -kernel vmlinux -serial stdio -append "panic=1 console=ttyS0 edd=off udevtimeout=6000 udev.event-timeout=6000 no_timer_check printk.time=1 cgroup_disable=memory usbcore.nousb cryptomgr.notests tsc=reliable 8250.nr_uarts=1 root=UUID=7cd9caf4-6491-41a5-b387-38af6fa2d638 selinux=0 guestfs_verbose=1 TERM=xterm-256color" >& /tmp/log ; echo -n . ; done
> 
> where "vmlinux" is a locally compiled kernel with CONFIG_PRINTK_TIME=y
> set.  I'm using the current git head.

Ah, that's much easier than whatever guestfish does, let me go run this
then.