On Sun, 2012-09-09 at 10:33 +0200, Geert Uytterhoeven wrote:

Ping?

Richard?  Are you going to pick up this patch?
It seems sensible.

Geert, I suggest sending it directly to Linus as a fix
if Richard doesn't respond in a few days.

On Thu, Aug 16, 2012 at 8:15 PM, Geert Uytterhoeven
[off-list ref] wrote:

quoted

The userspace part of UML uses the asm-offsets.h generator mechanism to
create definitions for UM_KERN_<LEVEL> that match the in-kernel
KERN_<LEVEL> constant definitions.

As of commit 04d2c8c83d0e3ac5f78aeede51babb3236200112 ("printk: convert
the format for KERN_<LEVEL> to a 2 byte pattern"), KERN_<LEVEL> is no
longer expanded to the literal '"<LEVEL>"', but to '"\001" "LEVEL"', i.e.
it contains two parts.

However, the combo of DEFINE_STR() in
arch/x86/um/shared/sysdep/kernel-offsets.h and sed-y in Kbuild doesn't
support string literals consisting of multiple parts. Hence for all
UM_KERN_<LEVEL> definitions, only the SOH character is retained in the actual
definition, while the remainder ends up in the comment. E.g. in
include/generated/asm-offsets.h we get

    #define UM_KERN_INFO "\001" /* "6" KERN_INFO */

instead of

    #define UM_KERN_INFO "\001" "6" /* KERN_INFO */

This causes spurious '^A' output in some kernel messages: