Patch "acpi/nfit, x86/mce: Handle only uncorrectable machine checks" has been added to the 4.19-stable tree

This is a note to let you know that I've just added the patch titled acpi/nfit, x86/mce: Handle only uncorrectable machine checks to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=s... The filename of the patch is: acpi-nfit-x86-mce-handle-only-uncorrectable-machine-checks.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable(a)vger.kernel.org&gt; know about it. From: Vishal Verma <vishal.l.verma(a)intel.com&gt; Date: Thu, 25 Oct 2018 18:37:28 -0600 Subject: acpi/nfit, x86/mce: Handle only uncorrectable machine checks From: Vishal Verma <vishal.l.verma(a)intel.com&gt; commit 5d96c9342c23ee1d084802dcf064caa67ecaa45b upstream. The MCE handler for nfit devices is called for memory errors on a Non-Volatile DIMM and adds the error location to a 'badblocks' list. This list is used by the various NVDIMM drivers to avoid consuming known poison locations during IO. The MCE handler gets called for both corrected and uncorrectable errors. Until now, both kinds of errors have been added to the badblocks list. However, corrected memory errors indicate that the problem has already been fixed by hardware, and the resulting interrupt is merely a notification to Linux. As far as future accesses to that location are concerned, it is perfectly fine to use, and thus doesn't need to be included in the above badblocks list. Add a check in the nfit MCE handler to filter out corrected mce events, and only process uncorrectable errors. Fixes: 6839a6d96f4e ("nfit: do an ARS scrub on hitting a latent media error") Reported-by: Omar Avelar <omar.avelar(a)intel.com&gt; Signed-off-by: Vishal Verma <vishal.l.verma(a)intel.com&gt; Signed-off-by: Borislav Petkov <bp(a)suse.de&gt; CC: Arnd Bergmann <arnd(a)arndb.de&gt; CC: Dan Williams <dan.j.williams(a)intel.com&gt; CC: Dave Jiang <dave.jiang(a)intel.com&gt; CC: elliott(a)hpe.com CC: "H. Peter Anvin" <hpa(a)zytor.com&gt; CC: Ingo Molnar <mingo(a)redhat.com&gt; CC: Len Brown <lenb(a)kernel.org&gt; CC: linux-acpi(a)vger.kernel.org CC: linux-edac <linux-edac(a)vger.kernel.org&gt; CC: linux-nvdimm(a)lists.01.org CC: Qiuxu Zhuo <qiuxu.zhuo(a)intel.com&gt; CC: "Rafael J. Wysocki" <rjw(a)rjwysocki.net&gt; CC: Ross Zwisler <zwisler(a)kernel.org&gt; CC: stable <stable(a)vger.kernel.org&gt; CC: Thomas Gleixner <tglx(a)linutronix.de&gt; CC: Tony Luck <tony.luck(a)intel.com&gt; CC: x86-ml <x86(a)kernel.org&gt; CC: Yazen Ghannam <yazen.ghannam(a)amd.com&gt; Link: http://lkml.kernel.org/r/20181026003729.8420-1-vishal.l.verma@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org&gt; --- arch/x86/include/asm/mce.h | 1 + arch/x86/kernel/cpu/mcheck/mce.c | 3 ++- drivers/acpi/nfit/mce.c | 4 ++-- 3 files changed, 5 insertions(+), 3 deletions(-) --- a/arch/x86/include/asm/mce.h +++ b/arch/x86/include/asm/mce.h @@ -216,6 +216,7 @@ static inline int umc_normaddr_to_sysadd int mce_available(struct cpuinfo_x86 *c); bool mce_is_memory_error(struct mce *m); +bool mce_is_correctable(struct mce *m); DECLARE_PER_CPU(unsigned, mce_exception_count); DECLARE_PER_CPU(unsigned, mce_poll_count); --- a/arch/x86/kernel/cpu/mcheck/mce.c +++ b/arch/x86/kernel/cpu/mcheck/mce.c @@ -534,7 +534,7 @@ bool mce_is_memory_error(struct mce *m) } EXPORT_SYMBOL_GPL(mce_is_memory_error); -static bool mce_is_correctable(struct mce *m) +bool mce_is_correctable(struct mce *m) { if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED) return false; @@ -544,6 +544,7 @@ static bool mce_is_correctable(struct mc return true; } +EXPORT_SYMBOL_GPL(mce_is_correctable); static bool cec_add_mce(struct mce *m) { --- a/drivers/acpi/nfit/mce.c +++ b/drivers/acpi/nfit/mce.c @@ -25,8 +25,8 @@ static int nfit_handle_mce(struct notifi struct acpi_nfit_desc *acpi_desc; struct nfit_spa *nfit_spa; - /* We only care about memory errors */ - if (!mce_is_memory_error(mce)) + /* We only care about uncorrectable memory errors */ + if (!mce_is_memory_error(mce) || mce_is_correctable(mce)) return NOTIFY_DONE; /* Patches currently in stable-queue which might be from vishal.l.verma(a)intel.com are queue-4.19/acpi-nfit-x86-mce-validate-a-mce-s-address-before-using-it.patch queue-4.19/acpi-nfit-x86-mce-handle-only-uncorrectable-machine-checks.patch