The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 78153dd45e7e0596ba32b15d02bda08e1513111e Mon Sep 17 00:00:00 2001

From: Dan Williams dan.j.williams@intel.com Date: Wed, 13 Feb 2019 09:28:40 -0800 Subject: [PATCH] nfit/ars: Avoid stale ARS results

Gate ARS result consumption on whether the OS issued start-ARS since the previous consumption. The BIOS may only clear its result buffers after a successful start-ARS.

Fixes: 0caeef63e6d2 ("libnvdimm: Add a poison list and export badblocks") Cc: stable@vger.kernel.org Reported-by: Krzysztof Rusocki krzysztof.rusocki@intel.com Reported-by: Vishal Verma vishal.l.verma@intel.com Reviewed-by: Toshi Kani toshi.kani@hpe.com Signed-off-by: Dan Williams dan.j.williams@intel.com

diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 629cf91649d2..5c9eb8d700d3 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -2652,7 +2652,10 @@ static int ars_start(struct acpi_nfit_desc *acpi_desc,

if (rc < 0) return rc; - return cmd_rc; + if (cmd_rc < 0) + return cmd_rc; + set_bit(ARS_VALID, &acpi_desc->scrub_flags); + return 0; }

static int ars_continue(struct acpi_nfit_desc *acpi_desc) @@ -2745,6 +2748,17 @@ static int ars_status_process_records(struct acpi_nfit_desc *acpi_desc) */ if (ars_status->out_length < 44) return 0; + + /* + * Ignore potentially stale results that are only refreshed + * after a start-ARS event. + */ + if (!test_and_clear_bit(ARS_VALID, &acpi_desc->scrub_flags)) { + dev_dbg(acpi_desc->dev, "skip %d stale records\n", + ars_status->num_records); + return 0; + } + for (i = 0; i < ars_status->num_records; i++) { /* only process full records */ if (ars_status->out_length @@ -3229,6 +3243,7 @@ static int acpi_nfit_register_regions(struct acpi_nfit_desc *acpi_desc) struct nfit_spa *nfit_spa; int rc;

+ set_bit(ARS_VALID, &acpi_desc->scrub_flags); list_for_each_entry(nfit_spa, &acpi_desc->spas, list) { switch (nfit_spa_type(nfit_spa->spa)) { case NFIT_SPA_VOLATILE: diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h index d14bad687fb8..0cbe5009eb2c 100644 --- a/drivers/acpi/nfit/nfit.h +++ b/drivers/acpi/nfit/nfit.h @@ -213,6 +213,7 @@ struct nfit_mem { enum scrub_flags { ARS_BUSY, ARS_CANCEL, + ARS_VALID, ARS_POLL, };