Boot stall regression from "printk for 5.19" merge

From: Marek Behún
Date: Sun Jun 19 2022 - 14:59:48 EST


Hello Linus, Petr, John,

the series
https://lore.kernel.org/linux-kernel/YouKQw72H7y9EJQK@alley/
merged by commit 537e62c865dc ("Merge tag 'printk-for-5.19' of
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux")

and in particular the commit 09c5ba0aa2fc ("printk: add kthread console
printers")

causes a regression on arm64 (Marvell CN9130-CRB board) where the
system boot freezes in most cases (and is unusable until restarted by
watchdog), or, in some cases boots, but the console output gets mangled
for a while (the serial console spits garbage characters).

The stall example:

...
[ 1.108141] io scheduler mq-deadline registered
[ 1.108143] io scheduler kyber registered
[ 1.163484] armada-ap806-pinctrl f06f4000.system-controller:pinctrl: registered pinctrl driver
[

Or another:

...
[ 1.108155] io scheduler mq-deadline registered
[ 1.108156] io scheduler kyber registered
[ 1.162991] armada-ap806-pinctrl f06f4000.system-controller:pinctrl: registered pinctrl driver
[ 1.163361] armada-cp110-pinctrl f2440000.system-controller:pinctrl: registered pinctrl driver
[ 1.180827] mv_xor_v2 f0400000.xor: Marvell Version 2 XOR driver
[

The garbage example:

...
[ 0.920951] raid6: using neon recovery algorithm
[ 0.921228] iommu: Default domain type: Translated
%

gb@k+cFL/[ 4.954974] DSA: tree 0 setup
[ 4.955286] cfg80211: Loading compiled-in X.509 certificates for regulatory database

I did not have time to look at the contents of the commit yet to try to
fix it myself, and won't have time for another two weeks. But I thought
I should let you know now.

Marek