The attached dmesg contains non printable chars 0x01 33 around "ACPI BIOS Error (bug): Could not resolve" which is a new issue compared to the dmesg of 4.17.2
System is a stable hardened Gentoo Linux at a ThinkPad T440s.
--
Toralf
PGP C4EACDDE 0076E94E
+Cc: Erik
On Tue, Jun 26, 2018 at 8:57 PM, Toralf Förster <[email protected]> wrote:
> The attached dmesg contains non printable chars 0x01 33 around "ACPI BIOS Error (bug): Could not resolve" which is a new issue compared to the dmesg of 4.17.2
>
> System is a stable hardened Gentoo Linux at a ThinkPad T440s.
I bet the below commit makes this.
commit 2e78935d1e27d31955ad2dad4abe6c453cf669fd
Author: Erik Schmauss <[email protected]>
Date: Fri Jun 1 12:06:43 2018 -0700
ACPICA: AML parser: attempt to continue loading table after error
So, it does add leading '\n' which flushes buffers followed by
printing the message you see. But, I'm guessing now, kernel adds a
default level since it's going to dmesg which you can see as
unprintable symbols.
Personally I'm not a fan of leading '\n':s since it brings more pain
than fixing something. It has special meaning (flushing buffers) and
many developers forget this.
--
With Best Regards,
Andy Shevchenko
> -----Original Message-----
> From: Andy Shevchenko [mailto:[email protected]]
> Sent: Wednesday, June 27, 2018 10:29 AM
> To: Toralf Förster <[email protected]>; Schmauss, Erik
> <[email protected]>
> Cc: ACPI Devel Maling List <[email protected]>; Linux Kernel <linux-
> [email protected]>
> Subject: Re: small dmesg regression in kernel 4.17.3
>
> +Cc: Erik
>
> On Tue, Jun 26, 2018 at 8:57 PM, Toralf Förster <[email protected]>
> wrote:
> > The attached dmesg contains non printable chars 0x01 33 around "ACPI
> > BIOS Error (bug): Could not resolve" which is a new issue compared to
> > the dmesg of 4.17.2
> >
> > System is a stable hardened Gentoo Linux at a ThinkPad T440s.
>
> I bet the below commit makes this.
>
> commit 2e78935d1e27d31955ad2dad4abe6c453cf669fd
> Author: Erik Schmauss <[email protected]>
> Date: Fri Jun 1 12:06:43 2018 -0700
>
> ACPICA: AML parser: attempt to continue loading table after error
>
>
Hi Andy,
> So, it does add leading '\n' which flushes buffers followed by printing the
> message you see. But, I'm guessing now, kernel adds a default level since it's
> going to dmesg which you can see as unprintable symbols.
What do you mean by a default level?
> Personally I'm not a fan of leading '\n':s since it brings more pain than fixing
> something. It has special meaning (flushing buffers) and many developers forget
> this.
This leading '\n' made it in Linux kernel unintentionally. It was originally intended as a change for acpiexec and it makes the dmesg look strange. I'll send out a fix.
Thanks for reporting it,
Erik
>
> --
> With Best Regards,
> Andy Shevchenko
On Friday, June 29, 2018 12:13:54 AM CEST Schmauss, Erik wrote:
>
> > -----Original Message-----
> > From: Andy Shevchenko [mailto:[email protected]]
> > Sent: Wednesday, June 27, 2018 10:29 AM
> > To: Toralf F?rster <[email protected]>; Schmauss, Erik
> > <[email protected]>
> > Cc: ACPI Devel Maling List <[email protected]>; Linux Kernel <linux-
> > [email protected]>
> > Subject: Re: small dmesg regression in kernel 4.17.3
> >
> > +Cc: Erik
> >
> > On Tue, Jun 26, 2018 at 8:57 PM, Toralf F?rster <[email protected]>
> > wrote:
> > > The attached dmesg contains non printable chars 0x01 33 around "ACPI
> > > BIOS Error (bug): Could not resolve" which is a new issue compared to
> > > the dmesg of 4.17.2
> > >
> > > System is a stable hardened Gentoo Linux at a ThinkPad T440s.
> >
> > I bet the below commit makes this.
> >
> > commit 2e78935d1e27d31955ad2dad4abe6c453cf669fd
> > Author: Erik Schmauss <[email protected]>
> > Date: Fri Jun 1 12:06:43 2018 -0700
> >
> > ACPICA: AML parser: attempt to continue loading table after error
> >
> >
> Hi Andy,
>
> > So, it does add leading '\n' which flushes buffers followed by printing the
> > message you see. But, I'm guessing now, kernel adds a default level since it's
> > going to dmesg which you can see as unprintable symbols.
>
> What do you mean by a default level?
>
> > Personally I'm not a fan of leading '\n':s since it brings more pain than fixing
> > something. It has special meaning (flushing buffers) and many developers forget
> > this.
>
> This leading '\n' made it in Linux kernel unintentionally. It was originally intended as a change for acpiexec and it makes the dmesg look strange. I'll send out a fix.
Which would be something like the patch below I suppose?
---
From: Rafael J. Wysocki <[email protected]>
Subject: [PATCH] ACPICA: Drop leading newlines from error messages
Commit 5088814a6e93 (ACPICA: AML parser: attempt to continue loading
table after error) unintentionally added leading newlines to error
messages emitted by ACPICA which caused unexpected things to be
printed to the kernel log. Drop these newlines (which effectively
reverts the part of commit 5088814a6e93 adding them).
Fixes: 5088814a6e93 (ACPICA: AML parser: attempt to continue loading table after error)
Reported-by: Toralf F?rster <[email protected]>
Reported-by: Guenter Roeck <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/acpi/acpica/uterror.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
Index: linux-pm/drivers/acpi/acpica/uterror.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpica/uterror.c
+++ linux-pm/drivers/acpi/acpica/uterror.c
@@ -182,19 +182,19 @@ acpi_ut_prefixed_namespace_error(const c
switch (lookup_status) {
case AE_ALREADY_EXISTS:
- acpi_os_printf("\n" ACPI_MSG_BIOS_ERROR);
+ acpi_os_printf(ACPI_MSG_BIOS_ERROR);
message = "Failure creating";
break;
case AE_NOT_FOUND:
- acpi_os_printf("\n" ACPI_MSG_BIOS_ERROR);
+ acpi_os_printf(ACPI_MSG_BIOS_ERROR);
message = "Could not resolve";
break;
default:
- acpi_os_printf("\n" ACPI_MSG_ERROR);
+ acpi_os_printf(ACPI_MSG_ERROR);
message = "Failure resolving";
break;
}
On Fri, Jun 29, 2018 at 1:13 AM, Schmauss, Erik <[email protected]> wrote:
>> On Tue, Jun 26, 2018 at 8:57 PM, Toralf Förster <[email protected]>
>> wrote:
>> > The attached dmesg contains non printable chars 0x01 33 around "ACPI
>> > BIOS Error (bug): Could not resolve" which is a new issue compared to
>> > the dmesg of 4.17.2
>> >
>> > System is a stable hardened Gentoo Linux at a ThinkPad T440s.
>>
>> I bet the below commit makes this.
>>
>> commit 2e78935d1e27d31955ad2dad4abe6c453cf669fd
>> Author: Erik Schmauss <[email protected]>
>> Date: Fri Jun 1 12:06:43 2018 -0700
>>
>> ACPICA: AML parser: attempt to continue loading table after error
>>
>>
> Hi Andy,
>
>> So, it does add leading '\n' which flushes buffers followed by printing the
>> message you see. But, I'm guessing now, kernel adds a default level since it's
>> going to dmesg which you can see as unprintable symbols.
>
> What do you mean by a default level?
I can't find fast the better example, though if you look at printk_get_level()
https://elixir.bootlin.com/linux/latest/source/include/linux/printk.h#L16
it will shed a light on a format. Thus, 0x01 0x33 means start of the
kernel error message (error is a level).
Kernel messaging protocol is defined in
https://elixir.bootlin.com/linux/latest/source/include/linux/kern_levels.h
This is my understanding on what's going on (I might be mistaken).
--
With Best Regards,
Andy Shevchenko
> -----Original Message-----
> From: [email protected] [mailto:linux-acpi-
> [email protected]] On Behalf Of Rafael J. Wysocki
> Sent: Friday, June 29, 2018 2:32 AM
> To: Schmauss, Erik <[email protected]>
> Cc: Andy Shevchenko <[email protected]>; Toralf F?rster
> <[email protected]>; Moore, Robert <[email protected]>; ACPI
> Devel Maling List <[email protected]>; Linux Kernel <linux-
> [email protected]>; Guenter Roeck <[email protected]>
> Subject: Re: small dmesg regression in kernel 4.17.3
>
> On Friday, June 29, 2018 12:13:54 AM CEST Schmauss, Erik wrote:
> >
> > > -----Original Message-----
> > > From: Andy Shevchenko [mailto:[email protected]]
> > > Sent: Wednesday, June 27, 2018 10:29 AM
> > > To: Toralf F?rster <[email protected]>; Schmauss, Erik
> > > <[email protected]>
> > > Cc: ACPI Devel Maling List <[email protected]>; Linux
> > > Kernel <linux- [email protected]>
> > > Subject: Re: small dmesg regression in kernel 4.17.3
> > >
> > > +Cc: Erik
> > >
> > > On Tue, Jun 26, 2018 at 8:57 PM, Toralf F?rster
> > > <[email protected]>
> > > wrote:
> > > > The attached dmesg contains non printable chars 0x01 33 around
> > > > "ACPI BIOS Error (bug): Could not resolve" which is a new issue
> > > > compared to the dmesg of 4.17.2
> > > >
> > > > System is a stable hardened Gentoo Linux at a ThinkPad T440s.
> > >
> > > I bet the below commit makes this.
> > >
> > > commit 2e78935d1e27d31955ad2dad4abe6c453cf669fd
> > > Author: Erik Schmauss <[email protected]>
> > > Date: Fri Jun 1 12:06:43 2018 -0700
> > >
> > > ACPICA: AML parser: attempt to continue loading table after error
> > >
> > >
> > Hi Andy,
> >
> > > So, it does add leading '\n' which flushes buffers followed by
> > > printing the message you see. But, I'm guessing now, kernel adds a
> > > default level since it's going to dmesg which you can see as unprintable
> symbols.
> >
> > What do you mean by a default level?
> >
> > > Personally I'm not a fan of leading '\n':s since it brings more pain
> > > than fixing something. It has special meaning (flushing buffers) and
> > > many developers forget this.
> >
> > This leading '\n' made it in Linux kernel unintentionally. It was originally
> intended as a change for acpiexec and it makes the dmesg look strange. I'll send
> out a fix.
>
> Which would be something like the patch below I suppose?
Yes, this is what I was thinking of
Thanks,
Erik
>
> ---
> From: Rafael J. Wysocki <[email protected]>
> Subject: [PATCH] ACPICA: Drop leading newlines from error messages
>
> Commit 5088814a6e93 (ACPICA: AML parser: attempt to continue loading table
> after error) unintentionally added leading newlines to error messages emitted by
> ACPICA which caused unexpected things to be printed to the kernel log. Drop
> these newlines (which effectively reverts the part of commit 5088814a6e93
> adding them).
>
> Fixes: 5088814a6e93 (ACPICA: AML parser: attempt to continue loading table
> after error)
> Reported-by: Toralf F?rster <[email protected]>
> Reported-by: Guenter Roeck <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
> ---
> drivers/acpi/acpica/uterror.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> Index: linux-pm/drivers/acpi/acpica/uterror.c
> =================================================================
> ==
> --- linux-pm.orig/drivers/acpi/acpica/uterror.c
> +++ linux-pm/drivers/acpi/acpica/uterror.c
> @@ -182,19 +182,19 @@ acpi_ut_prefixed_namespace_error(const c
> switch (lookup_status) {
> case AE_ALREADY_EXISTS:
>
> - acpi_os_printf("\n" ACPI_MSG_BIOS_ERROR);
> + acpi_os_printf(ACPI_MSG_BIOS_ERROR);
> message = "Failure creating";
> break;
>
> case AE_NOT_FOUND:
>
> - acpi_os_printf("\n" ACPI_MSG_BIOS_ERROR);
> + acpi_os_printf(ACPI_MSG_BIOS_ERROR);
> message = "Could not resolve";
> break;
>
> default:
>
> - acpi_os_printf("\n" ACPI_MSG_ERROR);
> + acpi_os_printf(ACPI_MSG_ERROR);
> message = "Failure resolving";
> break;
> }
>
> --
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