Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global list during initialization
This commit was tagged with:
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200011 Tested-by: Jean-Marc Lenoir Cc: All applicable stable@vger.kernel.org
making it sound like it was fixing an actual bug. This is not the case. The commit fixes a side issue discovered while investigating bug #200011. It does NOT fix bug #200011 itself (as explicitly reported by Jean-Marc at https://bugzilla.kernel.org/show_bug.cgi?id=200011#c65 ).
It does however cause regressions, despite what the commit message says. See:
https://bugzilla.kernel.org/show_bug.cgi?id=201721
and I expect more similar regressions, as ACPI resource conflicts are very frequent.
This commit was not stable material to start with. It is intrusive, presents a risk of side effects, and does not solve an actual bug that is bothering users.
Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works already).
Thanks,
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global list during initializationThis commit was tagged with:
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200011 Tested-by: Jean-Marc Lenoir Cc: All applicable <stable@vger.kernel.org>making it sound like it was fixing an actual bug. This is not the case. The commit fixes a side issue discovered while investigating bug #200011. It does NOT fix bug #200011 itself (as explicitly reported by Jean-Marc at https://bugzilla.kernel.org/show_bug.cgi?id=200011#c65 ).
It does however cause regressions, despite what the commit message says. See:
https://bugzilla.kernel.org/show_bug.cgi?id=201721
and I expect more similar regressions, as ACPI resource conflicts are very frequent.
This commit was not stable material to start with. It is intrusive, presents a risk of side effects, and does not solve an actual bug that is bothering users.
Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
thanks,
greg k-h
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global list during initialization(...) Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just can't be done in stable kernel series.
Thanks,
On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote:
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global list during initialization(...) Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just can't be done in stable kernel series.
Fair enough, I have seen reports about this already. Now reverted.
thanks,
greg k-h
-----Original Message----- From: Greg KH [mailto:greg@kroah.com] Sent: Tuesday, November 20, 2018 1:12 AM To: Jean Delvare jdelvare@suse.de Cc: stable@vger.kernel.org; Guenter Roeck linux@roeck-us.net; Schmauss, Erik erik.schmauss@intel.com; Wysocki, Rafael J rafael.j.wysocki@intel.com Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote:
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global listduring initialization
(...)
Hi,
Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works
already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
Hello,
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just can't be done in stable kernel series.
I would like to give you more context.
There was a fairly complicated change that occurred in 4.17 and we caused a regression by forgetting to add region addresses in a global list during operation region initialization. We found the regression when bug reporters tried to boot their macbook pro and asus laptop and saw that there was a difference in behavior when drivers are being loaded
So what I am trying to say is that we have been emitting these errors for a while before we caused the regression. The goal with this patch is to keep the behavior the same as kernels older than 4.17 where warnings are printed to dmesg due to resource conflicts.
Erik
Fair enough, I have seen reports about this already. Now reverted.
thanks,
greg k-h
On Tue, Nov 20, 2018 at 06:30:22PM +0000, Schmauss, Erik wrote:
-----Original Message----- From: Greg KH [mailto:greg@kroah.com] Sent: Tuesday, November 20, 2018 1:12 AM To: Jean Delvare jdelvare@suse.de Cc: stable@vger.kernel.org; Guenter Roeck linux@roeck-us.net; Schmauss, Erik erik.schmauss@intel.com; Wysocki, Rafael J rafael.j.wysocki@intel.com Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote:
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in global listduring initialization
(...)
Hi,
Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works
already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
Hello,
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just can't be done in stable kernel series.
I would like to give you more context.
There was a fairly complicated change that occurred in 4.17 and we caused a regression by forgetting to add region addresses in a global list during operation region initialization. We found the regression when bug reporters tried to boot their macbook pro and asus laptop and saw that there was a difference in behavior when drivers are being loaded
So what I am trying to say is that we have been emitting these errors for a while before we caused the regression. The goal with this patch is to keep the behavior the same as kernels older than 4.17 where warnings are printed to dmesg due to resource conflicts.
Ok, so does this mean it belongs in 4.19.y? (4.18.y is about to go end-of-life in a few hours)
Or does this mean it should just stay in 4.20?
confused,
greg k-h
-----Original Message----- From: Greg KH [mailto:greg@kroah.com] Sent: Wednesday, November 21, 2018 12:04 AM To: Schmauss, Erik erik.schmauss@intel.com Cc: Jean Delvare jdelvare@suse.de; stable@vger.kernel.org; Guenter Roeck linux@roeck-us.net; Wysocki, Rafael J rafael.j.wysocki@intel.com; Moore, Robert robert.moore@intel.com Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
On Tue, Nov 20, 2018 at 06:30:22PM +0000, Schmauss, Erik wrote:
-----Original Message----- From: Greg KH [mailto:greg@kroah.com] Sent: Tuesday, November 20, 2018 1:12 AM To: Jean Delvare jdelvare@suse.de Cc: stable@vger.kernel.org; Guenter Roeck linux@roeck-us.net; Schmauss, Erik erik.schmauss@intel.com; Wysocki, Rafael J rafael.j.wysocki@intel.com Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote:
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
On Tue, Nov 20, 2018 at 09:46:49AM +0100, Jean Delvare wrote:
Dear stable kernel team,
In stable kernel 4.19.2, the following upstream commit was included:
commit 4abb951b73ff0a8a979113ef185651aa3c8da19b Author: Erik Schmauss Date: Wed Oct 17 14:09:35 2018 -0700
ACPICA: AML interpreter: add region addresses in globallist during initialization
(...)
Hi,
Please revert this commit from future stable kernels on all affected branches (I think only 4.18.19 and 4.19.2 are affected at the moment, but maybe other affected releases are in the works
already).
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
Hello,
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just
can't be done in stable kernel series.
I would like to give you more context.
There was a fairly complicated change that occurred in 4.17 and we caused a regression by forgetting to add region addresses in a global list during operation region initialization. We found the regression when bug reporters tried to boot their macbook pro and asus laptop and saw that there was a difference in behavior when drivers are being loaded
So what I am trying to say is that we have been emitting these errors for a while before we caused the regression. The goal with this patch is to keep the behavior the same as kernels older than 4.17 where warnings are printed to dmesg due to resource conflicts.
Ok, so does this mean it belongs in 4.19.y? (4.18.y is about to go end-of-life in a few hours)
Yes, it should be in 4.19.y
Erik
Or does this mean it should just stay in 4.20?
confused,
greg k-h
Hi Erik,
On Tue, 20 Nov 2018 18:30:22 +0000, Schmauss, Erik wrote:
-----Original Message----- From: Greg KH [mailto:greg@kroah.com] Sent: Tuesday, November 20, 2018 1:12 AM To: Jean Delvare jdelvare@suse.de Cc: stable@vger.kernel.org; Guenter Roeck linux@roeck-us.net; Schmauss, Erik erik.schmauss@intel.com; Wysocki, Rafael J rafael.j.wysocki@intel.com Subject: Re: Please revert "ACPICA: AML interpreter: add region addresses in global list during initialization"
On Tue, Nov 20, 2018 at 10:03:59AM +0100, Jean Delvare wrote:
On Tue, 20 Nov 2018 09:54:19 +0100, Greg KH wrote:
Ok, I'll go revert this, but shouldn't it also be reverted in Linus's tree as well?
No. As I understand it (with my limited knowledge of ACPICA), the change itself is correct. The problem is that it will detect resource conflicts which were unnoticed before, and that will prevent drivers from loading. Some of them may be addressed with driver fixes or new drivers. Others are false positives (due to bogus BIOS) which users will have to work around with acpi_resource_conflicts=lax. We have been through this before, nothing new really, but it takes years to address such problems. This just can't be done in stable kernel series.
I would like to give you more context.
There was a fairly complicated change that occurred in 4.17 and we caused a regression by forgetting to add region addresses in a global list during operation region initialization. We found the regression when bug reporters tried to boot their macbook pro and asus laptop and saw that there was a difference in behavior when drivers are being loaded
Commit 4abb951b73ff0a8a979113ef185651aa3c8da19b has no Fixes tag. Which commit introduced the regression? Can you point me to the associated bug reports?
So what I am trying to say is that we have been emitting these errors for a while before we caused the regression. The goal with this patch is to keep the behavior the same as kernels older than 4.17 where warnings are printed to dmesg due to resource conflicts.
Fine with me for upstream, but I still need to be convinced that it belongs to stable series. For now, the only 2 related bugs I know of are #200011 (which is NOT fixed by commit 4abb951b73ff0a8a979113ef185651aa3c8da19b) and #201721 (which is caused by that commit). 1 vs 0, revert wins. If you want me to change my mind, you must provide additional data points proving that commit 4abb951b73ff0a8a979113ef185651aa3c8da19b solves more functional regressions than it causes.
Thanks,
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Jean Delvare -
Schmauss, Erik