Hi,
> From: linux-acpi-ow...@vger.kernel.org
> [mailto:linux-acpi-ow...@vger.kernel.org] On Behalf Of Dan
> Williams
> Subject: [PATCH] acpi: fix acpi_get_table() leak / acpi-sysfs denial of
> service
>
> 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.
For now, should just return AE_OK instead of AE_LIMIT in acpi_tb_get_table().
Otherwise this fix will not be sufficient to fix all possible problem
Unless we can add acpi_put_table() for all acpi_get_table() invocation.
Let me send a patch for you to try.
Thanks and best regards
Lv
>
> Cc: <sta...@vger.kernel.org>
> Cc: Zhang Rui <rui.zh...@intel.com>
> Cc: Rafael Wysocki <rafael.j.wyso...@intel.com>
> Cc: Kristin Jacque <kristin.jac...@intel.com>
> Cc: Tiffany Kasanicky <tiffany.j.kasani...@intel.com>
> Cc: Ryon Jensen <ryon.jen...@intel.com>
> Reported-by: Anush Seetharaman <anush.seethara...@intel.com>
> Fixes: 1c8fce27e275 ("ACPI: introduce drivers/acpi/sysfs.c")
> Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
> ---
> 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 cf05ae973381..531ddabf0390 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 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);
> + return rc;
> }
>
> static int acpi_table_attr_init(struct kobject *tables_obj,
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
