[PATCH v4 3/4] ACPI: sysfs: Fix acpi_get_table() leak

From: Lv Zheng
Date: Tue May 09 2017 - 01:57:56 EST


From: Dan Williams <dan.j.williams@xxxxxxxxx>

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)

Add the missing acpi_put_table() so the table ->validation_count is
decremented after each read.

Reported-by: Anush Seetharaman <anush.seetharaman@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
---
drivers/acpi/sysfs.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
index 1b5ee1e..2bbf722 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -333,14 +333,17 @@ static ssize_t acpi_table_show(struct file *filp, struct kobject *kobj,
container_of(bin_attr, struct acpi_table_attr, attr);
struct acpi_table_header *table_header = NULL;
acpi_status status;
+ ssize_t len;

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);
+ len = memory_read_from_buffer(buf, count, &offset,
+ table_header, table_header->length);
+ acpi_put_table(table_header);
+ return len;
}

static int acpi_table_attr_init(struct kobject *tables_obj,
--
2.7.4