This is a note to let you know that I've just added the patch titled
x86/nmi_watchdog: Fix old-style NMI watchdog regression on old Intel CPUs
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-nmi_watchdog-fix-old-style-nmi-watchdog-regression-on-old-intel-cpus.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a8383dfb2138742a1bb77b481ada047aededa2ba Mon Sep 17 00:00:00 2001
From: CodyYao-oc <CodyYao-oc@xxxxxxxxxxx>
Date: Mon, 7 Jun 2021 10:53:35 +0800
Subject: x86/nmi_watchdog: Fix old-style NMI watchdog regression on old Intel CPUs
From: CodyYao-oc <CodyYao-oc@xxxxxxxxxxx>
commit a8383dfb2138742a1bb77b481ada047aededa2ba upstream.
The following commit:
3a4ac121c2ca ("x86/perf: Add hardware performance events support for Zhaoxin CPU.")
Got the old-style NMI watchdog logic wrong and broke it for basically every
Intel CPU where it was active. Which is only truly old CPUs, so few people noticed.
On CPUs with perf events support we turn off the old-style NMI watchdog, so it
was pretty pointless to add the logic for X86_VENDOR_ZHAOXIN to begin with ... :-/
Anyway, the fix is to restore the old logic and add a 'break'.
[ mingo: Wrote a new changelog. ]
Fixes: 3a4ac121c2ca ("x86/perf: Add hardware performance events support for Zhaoxin CPU.")
Signed-off-by: CodyYao-oc <CodyYao-oc@xxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210607025335.9643-1-CodyYao-oc@xxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perfctr-watchdog.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/perfctr-watchdog.c
+++ b/arch/x86/kernel/cpu/perfctr-watchdog.c
@@ -63,7 +63,7 @@ static inline unsigned int nmi_perfctr_m
case 15:
return msr - MSR_P4_BPU_PERFCTR0;
}
- fallthrough;
+ break;
case X86_VENDOR_ZHAOXIN:
case X86_VENDOR_CENTAUR:
return msr - MSR_ARCH_PERFMON_PERFCTR0;
@@ -96,7 +96,7 @@ static inline unsigned int nmi_evntsel_m
case 15:
return msr - MSR_P4_BSU_ESCR0;
}
- fallthrough;
+ break;
case X86_VENDOR_ZHAOXIN:
case X86_VENDOR_CENTAUR:
return msr - MSR_ARCH_PERFMON_EVENTSEL0;
Patches currently in stable-queue which might be from CodyYao-oc@xxxxxxxxxxx are
queue-5.10/x86-nmi_watchdog-fix-old-style-nmi-watchdog-regression-on-old-intel-cpus.patch
