All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff
@ 2023-04-25 19:26 Tony Battersby
  2023-04-25 19:39 ` Borislav Petkov
                   ` (3 more replies)
  0 siblings, 4 replies; 23+ messages in thread
From: Tony Battersby @ 2023-04-25 19:26 UTC (permalink / raw)
  To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, x86
  Cc: H. Peter Anvin, Mario Limonciello, Tom Lendacky,
	linux-kernel@vger.kernel.org

In stop_this_cpu(), make sure the CPUID leaf exists before accessing the
leaf.  This fixes a lockup on poweroff 50% of the time due to the wrong
branch being taken randomly on some CPUs (seen on Supermicro X8DTH-6F
with Intel Xeon X5650).

Fixes: 08f253ec3767 ("x86/cpu: Clear SME feature flag when not in use")
Cc: <stable@vger.kernel.org> # 5.18+
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
---

NOTE: I don't have any AMD CPUs to test, so I was unable to fully test
this patch.  Could someone with an AMD CPU that supports SME please test
this and make sure it calls native_wbinvd()?


 arch/x86/kernel/process.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b650cde3f64d..26aa32e8f636 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -754,13 +754,15 @@ bool xen_set_default_idle(void)
 
 void __noreturn stop_this_cpu(void *dummy)
 {
+	struct cpuinfo_x86 *c = this_cpu_ptr(&cpu_info);
+
 	local_irq_disable();
 	/*
 	 * Remove this CPU:
 	 */
 	set_cpu_online(smp_processor_id(), false);
 	disable_local_APIC();
-	mcheck_cpu_clear(this_cpu_ptr(&cpu_info));
+	mcheck_cpu_clear(c);
 
 	/*
 	 * Use wbinvd on processors that support SME. This provides support
@@ -774,7 +776,8 @@ void __noreturn stop_this_cpu(void *dummy)
 	 * Test the CPUID bit directly because the machine might've cleared
 	 * X86_FEATURE_SME due to cmdline options.
 	 */
-	if (cpuid_eax(0x8000001f) & BIT(0))
+	if (c->extended_cpuid_level >= 0x8000001f &&
+	    (cpuid_eax(0x8000001f) & BIT(0)))
 		native_wbinvd();
 	for (;;) {
 		/*
-- 
2.25.1


^ permalink raw reply related	[flat|nested] 23+ messages in thread
end of thread, other threads:[~2023-06-20 13:02 UTC | newest]

Thread overview: 23+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-04-25 19:26 [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff Tony Battersby
2023-04-25 19:39 ` Borislav Petkov
2023-04-25 19:58   ` Tony Battersby
2023-04-25 20:03 ` Dave Hansen
2023-04-25 20:34   ` Dave Hansen
2023-04-25 21:06     ` Borislav Petkov
2023-04-25 21:05   ` Thomas Gleixner
2023-04-25 22:29     ` Dave Hansen
2023-04-25 23:00       ` Thomas Gleixner
2023-04-26  0:10       ` H. Peter Anvin
2023-04-26 14:45     ` Tony Battersby
2023-04-26 16:37       ` Thomas Gleixner
2023-04-26 17:37         ` Tony Battersby
2023-04-26 17:41           ` [PATCH v2] x86/cpu: fix SME test in stop_this_cpu() Tony Battersby
2023-05-22 14:07             ` [PATCH v2 RESEND] " Tony Battersby
2023-04-26 17:51           ` [PATCH RFC] x86/cpu: fix intermittent lockup on poweroff Tom Lendacky
2023-04-26 18:15             ` Dave Hansen
2023-04-26 19:18               ` Tom Lendacky
2023-04-26 22:02                 ` Andi Kleen
2023-04-26 23:20                   ` Thomas Gleixner
2023-04-26 20:00             ` Thomas Gleixner
2023-06-20 13:00 ` [tip: x86/core] x86/smp: Dont access non-existing CPUID leaf tip-bot2 for Tony Battersby
2023-06-20 13:00 ` [tip: x86/core] x86/smp: Make stop_other_cpus() more robust tip-bot2 for Thomas Gleixner

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.