* [tip:x86/urgent] x86/mce: Ensure offline CPUs don' t participate in rendezvous process
2015-12-10 10:12 ` [PATCH] x86/mce: Ensure offline CPUs don't participate in rendezvous process Borislav Petkov
@ 2015-12-14 8:18 ` tip-bot for Ashok Raj
2015-12-19 9:15 ` tip-bot for Ashok Raj
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Ashok Raj @ 2015-12-14 8:18 UTC (permalink / raw)
To: linux-tip-commits
Cc: tony.luck, torvalds, ashok.raj, mingo, stable, hpa, linux-kernel,
peterz, tglx, linux-edac, bp
Commit-ID: 06f337b7c7eb86254c86e8e717273d1e356d5a1b
Gitweb: http://git.kernel.org/tip/06f337b7c7eb86254c86e8e717273d1e356d5a1b
Author: Ashok Raj <ashok.raj@intel.com>
AuthorDate: Thu, 10 Dec 2015 11:12:26 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 11 Dec 2015 08:59:48 +0100
x86/mce: Ensure offline CPUs don't participate in rendezvous process
Intel's MCA implementation broadcasts MCEs to all CPUs on the
node. This poses a problem for offlined CPUs which cannot
participate in the rendezvous process:
Kernel panic - not syncing: Timeout: Not all CPUs entered broadcast exception handler
Kernel Offset: disabled
Rebooting in 100 seconds..
More specifically, Linux does a soft offline of a CPU when
writing a 0 to /sys/devices/system/cpu/cpuX/online, which
doesn't prevent the #MC exception from being broadcasted to that
CPU.
Ensure that offline CPUs don't participate in the MCE rendezvous
and clear the RIP valid status bit so that a second MCE won't
cause a shutdown.
Without the patch, mce_start() will increment mce_callin and
wait for all CPUs. Offlined CPUs should avoid participating in
the rendezvous process altogether.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1449742346-21470-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/mcheck/mce.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index c5b0d56..7e8a736 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -999,6 +999,17 @@ void do_machine_check(struct pt_regs *regs, long error_code)
int flags = MF_ACTION_REQUIRED;
int lmce = 0;
+ /* If this CPU is offline, just bail out. */
+ if (cpu_is_offline(smp_processor_id())) {
+ u64 mcgstatus;
+
+ mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
+ if (mcgstatus & MCG_STATUS_RIPV) {
+ mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
+ return;
+ }
+ }
+
ist_enter(regs);
this_cpu_inc(mce_exception_count);
^ permalink raw reply [flat|nested] 4+ messages in thread* [tip:x86/urgent] x86/mce: Ensure offline CPUs don' t participate in rendezvous process
2015-12-10 10:12 ` [PATCH] x86/mce: Ensure offline CPUs don't participate in rendezvous process Borislav Petkov
2015-12-14 8:18 ` [tip:x86/urgent] x86/mce: Ensure offline CPUs don' t " tip-bot for Ashok Raj
@ 2015-12-19 9:15 ` tip-bot for Ashok Raj
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Ashok Raj @ 2015-12-19 9:15 UTC (permalink / raw)
To: linux-tip-commits
Cc: mingo, tglx, peterz, ashok.raj, torvalds, hpa, bp, linux-kernel,
linux-edac, tony.luck, stable
Commit-ID: d90167a941f62860f35eb960e1012aa2d30e7e94
Gitweb: http://git.kernel.org/tip/d90167a941f62860f35eb960e1012aa2d30e7e94
Author: Ashok Raj <ashok.raj@intel.com>
AuthorDate: Thu, 10 Dec 2015 11:12:26 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Sat, 19 Dec 2015 09:55:31 +0100
x86/mce: Ensure offline CPUs don't participate in rendezvous process
Intel's MCA implementation broadcasts MCEs to all CPUs on the
node. This poses a problem for offlined CPUs which cannot
participate in the rendezvous process:
Kernel panic - not syncing: Timeout: Not all CPUs entered broadcast exception handler
Kernel Offset: disabled
Rebooting in 100 seconds..
More specifically, Linux does a soft offline of a CPU when
writing a 0 to /sys/devices/system/cpu/cpuX/online, which
doesn't prevent the #MC exception from being broadcasted to that
CPU.
Ensure that offline CPUs don't participate in the MCE rendezvous
and clear the RIP valid status bit so that a second MCE won't
cause a shutdown.
Without the patch, mce_start() will increment mce_callin and
wait for all CPUs. Offlined CPUs should avoid participating in
the rendezvous process altogether.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
[ Massage commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/1449742346-21470-2-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/kernel/cpu/mcheck/mce.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index c5b0d56..7e8a736 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -999,6 +999,17 @@ void do_machine_check(struct pt_regs *regs, long error_code)
int flags = MF_ACTION_REQUIRED;
int lmce = 0;
+ /* If this CPU is offline, just bail out. */
+ if (cpu_is_offline(smp_processor_id())) {
+ u64 mcgstatus;
+
+ mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
+ if (mcgstatus & MCG_STATUS_RIPV) {
+ mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
+ return;
+ }
+ }
+
ist_enter(regs);
this_cpu_inc(mce_exception_count);
^ permalink raw reply [flat|nested] 4+ messages in thread