The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 76357cc192acd78b85d4c3380d07f139d906dfe8
Gitweb: https://git.kernel.org/tip/76357cc192acd78b85d4c3380d07f139d906dfe8
Author: Thomas Gleixner <[email protected]>
AuthorDate: Tue, 28 May 2024 22:21:31 +02:00
Committer: Borislav Petkov (AMD) <[email protected]>
CommitterDate: Wed, 29 May 2024 11:01:20 +02:00
x86/topology/amd: Evaluate SMT in CPUID leaf 0x8000001e only on family 0x17 and greater
The new AMD/HYGON topology parser evaluates the SMT information in CPUID leaf
0x8000001e unconditionally while the original code restricted it to CPUs with
family 0x17 and greater.
This breaks family 0x15 CPUs which advertise that leaf and have a non-zero
value in the SMT section. The machine boots, but the scheduler complains loudly
about the mismatch of the core IDs:
WARNING: CPU: 1 PID: 0 at kernel/sched/core.c:6482 sched_cpu_starting+0x183/0x250
WARNING: CPU: 0 PID: 1 at kernel/sched/topology.c:2408 build_sched_domains+0x76b/0x12b0
Add the condition back to cure it.
[ bp: Make it actually build because grandpa is not concerned with
trivial stuff. :-P ]
Fixes: f7fb3b2dd92c ("x86/cpu: Provide an AMD/HYGON specific topology parser")
Closes: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/56
Reported-by: Tim Teichmann <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Tested-by: Tim Teichmann <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/7skhx6mwe4hxiul64v6azhlxnokheorksqsdbp7qw6g2jduf6c@7b5pvomauugk
---
arch/x86/kernel/cpu/topology_amd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/topology_amd.c b/arch/x86/kernel/cpu/topology_amd.c
index d419dee..7d476fa 100644
--- a/arch/x86/kernel/cpu/topology_amd.c
+++ b/arch/x86/kernel/cpu/topology_amd.c
@@ -84,9 +84,9 @@ static bool parse_8000_001e(struct topo_scan *tscan, bool has_topoext)
/*
* If leaf 0xb is available, then the domain shifts are set
- * already and nothing to do here.
+ * already and nothing to do here. Only valid for family >= 0x17.
*/
- if (!has_topoext) {
+ if (!has_topoext && tscan->c->x86 >= 0x17) {
/*
* Leaf 0x80000008 set the CORE domain shift already.
* Update the SMT domain, but do not propagate it.
On 24/05/29 09:25AM, tip-bot2 for Thomas Gleixner wrote:
> The following commit has been merged into the x86/urgent branch of tip:
>
> Commit-ID: 76357cc192acd78b85d4c3380d07f139d906dfe8
> Gitweb: https://git.kernel.org/tip/76357cc192acd78b85d4c3380d07f139d906dfe8
> Author: Thomas Gleixner <[email protected]>
> AuthorDate: Tue, 28 May 2024 22:21:31 +02:00
> Committer: Borislav Petkov (AMD) <[email protected]>
> CommitterDate: Wed, 29 May 2024 11:01:20 +02:00
>
> [...]
>
> Fixes: f7fb3b2dd92c ("x86/cpu: Provide an AMD/HYGON specific topology parser")
> Closes: https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/issues/56
> Reported-by: Tim Teichmann <[email protected]>
> Signed-off-by: Thomas Gleixner <[email protected]>
> Signed-off-by: Borislav Petkov (AMD) <[email protected]>
> Tested-by: Tim Teichmann <[email protected]>
> Cc: [email protected]
> Link: https://lore.kernel.org/r/7skhx6mwe4hxiul64v6azhlxnokheorksqsdbp7qw6g2jduf6c@7b5pvomauugk
Hey Thomas, hey Borislav,
it seems like somehow the patch has lost the following two trailers
compared to the list variant[0] while being applied:
Bisected-by: Christian Heusel <[email protected]>
Cc: [email protected]
Did that happen on purpose or did some scripts fail?
Cheers,
Chris
[0]: https://lore.kernel.org/lkml/8734q1bsc4.ffs@tglx/
On Thu, May 30, 2024 at 12:40:50AM +0200, Christian Heusel wrote:
> it seems like somehow the patch has lost the following two trailers
> compared to the list variant[0] while being applied:
>
> Bisected-by: Christian Heusel <[email protected]>
> Cc: [email protected]
>
> Did that happen on purpose or did some scripts fail?
Well, we don't add unknown tags because it was getting unwieldy and
Bisected-by is not really one we do. I can offer
Reported-by: Christian Heusel <[email protected]>
as bisection is important work and it should be documented.
How does that sound?
Thx.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
On 24/05/30 10:59AM, Borislav Petkov wrote:
> On Thu, May 30, 2024 at 12:40:50AM +0200, Christian Heusel wrote:
> > it seems like somehow the patch has lost the following two trailers
> > compared to the list variant[0] while being applied:
> >
> > Bisected-by: Christian Heusel <[email protected]>
> > Cc: [email protected]
> >
> > Did that happen on purpose or did some scripts fail?
>
> Well, we don't add unknown tags because it was getting unwieldy and
> Bisected-by is not really one we do. I can offer
>
> Reported-by: Christian Heusel <[email protected]>
>
> as bisection is important work and it should be documented.
>
> How does that sound?
Sounds good! I thought it was a thing because I saw it used in a few
places, i.e. here:
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=e37617c8e53a1f7fcba6d5e1041f4fd8a2425c27
I'll keep it in mind for future bug reports! :)
Have a nice week,
Chris
On Thu, May 30, 2024 at 02:21:28PM +0200, Christian Heusel wrote:
> Sounds good! I thought it was a thing because I saw it used in a few
> places, i.e. here:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=e37617c8e53a1f7fcba6d5e1041f4fd8a2425c27
Yeah, I'm polling internally whether we should add this new tag. But
Reported-by pretty much does it...
> I'll keep it in mind for future bug reports! :)
>
> Have a nice week,
Thanks and ditto. :-)
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette