Messages in this thread Patch in this message | | | Date | Tue, 7 Nov 2017 02:15:46 -0800 | From | tip-bot for Yazen Ghannam <> | Subject | [tip:ras/core] x86/MCE/AMD: Always give panic severity for UC errors in kernel context |
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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 {
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