From: tip-bot for Yazen Ghannam <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tony.luck@intel.com, bp@suse.de, yazen.ghannam@amd.com,
peterz@infradead.org, linux-kernel@vger.kernel.org,
hpa@zytor.com, torvalds@linux-foundation.org,
linux-edac@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org
Subject: [tip:ras/core] x86/MCE/AMD: Always give panic severity for UC errors in kernel context
Date: Tue, 7 Nov 2017 02:15:46 -0800 [thread overview]
Message-ID: <tip-d65dfc81bb3894fdb68cbc74bbf5fb48d2354071@git.kernel.org> (raw)
In-Reply-To: <20171106174633.13576-1-bp@alien8.de>
Commit-ID: d65dfc81bb3894fdb68cbc74bbf5fb48d2354071
Gitweb: https://git.kernel.org/tip/d65dfc81bb3894fdb68cbc74bbf5fb48d2354071
Author: Yazen Ghannam <yazen.ghannam@amd.com>
AuthorDate: Mon, 6 Nov 2017 18:46:32 +0100
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Nov 2017 11:07:50 +0100
x86/MCE/AMD: Always give panic severity for UC errors in kernel context
The AMD severity grading function was introduced in kernel 4.1. The
current logic can possibly give MCE_AR_SEVERITY for uncorrectable
errors in kernel context. The system may then get stuck in a loop as
memory_failure() will try to handle the bad kernel memory and find it
busy.
Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD
systems.
After:
b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries")
was accepted in v4.6, this issue was masked because of the tail-end attempt
at kernel mode recovery in the #MC handler.
However, uncorrectable errors IN_KERNEL context should always be considered
unrecoverable and cause a panic.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.9.x
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Fixes: bf80bbd7dcf5 (x86/mce: Add an AMD severities-grading function)
Link: http://lkml.kernel.org/r/20171106174633.13576-1-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/mcheck/mce-severity.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
index 87cc9ab..4b81876 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-severity.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -245,6 +245,9 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_exc
if (m->status & MCI_STATUS_UC) {
+ if (ctx == IN_KERNEL)
+ return MCE_PANIC_SEVERITY;
+
/*
* On older systems where overflow_recov flag is not present, we
* should simply panic if an error overflow occurs. If
@@ -255,10 +258,6 @@ static int mce_severity_amd(struct mce *m, int tolerant, char **msg, bool is_exc
if (mce_flags.smca)
return mce_severity_amd_smca(m, ctx);
- /* software can try to contain */
- if (!(m->mcgstatus & MCG_STATUS_RIPV) && (ctx == IN_KERNEL))
- return MCE_PANIC_SEVERITY;
-
/* kill current process */
return MCE_AR_SEVERITY;
} else {
prev parent reply other threads:[~2017-11-07 10:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-06 17:46 [PATCH 1/2] x86/MCE/AMD: Always give panic severity for UC errors in kernel context Borislav Petkov
2017-11-06 17:46 ` [PATCH 2/2] x86/MCE/AMD: Fix mce_severity_amd_smca() signature Borislav Petkov
2017-11-07 10:16 ` [tip:ras/core] " tip-bot for Yazen Ghannam
2017-11-07 10:15 ` tip-bot for Yazen Ghannam [this message]
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