Patch "ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service" has been added to the 4.11-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service

to the 4.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     acpi-sysfs-fix-acpi_get_table-leak-acpi-sysfs-denial-of-service.patch
and it can be found in the queue-4.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 0de0e198bc7191a0e46cf71f66fec4d07ca91396 Mon Sep 17 00:00:00 2001
From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 25 Apr 2017 12:58:31 -0700
Subject: ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service

From: Dan Williams <dan.j.williams@intel.com>

commit 0de0e198bc7191a0e46cf71f66fec4d07ca91396 upstream.

Reading an ACPI table through the /sys/firmware/acpi/tables interface
more than 65,536 times leads to the following log message:

 ACPI Error: Table ffff88033595eaa8, Validation count is zero after increment
  (20170119/tbutils-423)

...and the table being unavailable until the next reboot. Add the
missing acpi_put_table() so the table ->validation_count is decremented
after each read.

Reported-by: Anush Seetharaman <anush.seetharaman@intel.com>
Fixes: 174cc7187e6f "ACPICA: Tables: Back port acpi_get_table_with_size() ..."
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/acpi/sysfs.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -333,14 +333,17 @@ static ssize_t acpi_table_show(struct fi
 	    container_of(bin_attr, struct acpi_table_attr, attr);
 	struct acpi_table_header *table_header = NULL;
 	acpi_status status;
+	ssize_t rc;
 
 	status = acpi_get_table(table_attr->name, table_attr->instance,
 				&table_header);
 	if (ACPI_FAILURE(status))
 		return -ENODEV;
 
-	return memory_read_from_buffer(buf, count, &offset,
-				       table_header, table_header->length);
+	rc = memory_read_from_buffer(buf, count, &offset, table_header,
+			table_header->length);
+	acpi_put_table(table_header);
+	return rc;
 }
 
 static int acpi_table_attr_init(struct kobject *tables_obj,


Patches currently in stable-queue which might be from dan.j.williams@intel.com are

queue-4.11/acpica-tables-fix-regression-introduced-by-a-too-early-mechanism-enabling.patch
queue-4.11/acpi-sysfs-fix-acpi_get_table-leak-acpi-sysfs-denial-of-service.patch