4.9-stable review patch. If anyone has any objections, please let me know.
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From: Dan Williams dan.j.williams@intel.com
commit 78727137fdf49edf9f731bde79d7189067b4047a upstream.
There is a small window whereby ARS scan requests can schedule work that userspace will miss when polling scrub_show. Hold the init_mutex lock over calls to report the status to close this potential escape. Also, make sure that requests to cancel the ARS workqueue are treated as an idle event.
Cc: stable@vger.kernel.org Cc: Vishal Verma vishal.l.verma@intel.com Fixes: 37b137ff8c83 ("nfit, libnvdimm: allow an ARS scrub...") Reviewed-by: Dave Jiang dave.jiang@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/acpi/nfit/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -967,8 +967,11 @@ static ssize_t scrub_show(struct device if (nd_desc) { struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+ mutex_lock(&acpi_desc->init_mutex); rc = sprintf(buf, "%d%s", acpi_desc->scrub_count, - (work_busy(&acpi_desc->work)) ? "+\n" : "\n"); + work_busy(&acpi_desc->work) + && !acpi_desc->cancel ? "+\n" : "\n"); + mutex_unlock(&acpi_desc->init_mutex); } device_unlock(dev); return rc;