Hi, > From: linux-acpi-owner@xxxxxxxxxxxxxxx [mailto:linux-acpi-owner@xxxxxxxxxxxxxxx] 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: <stable@xxxxxxxxxxxxxxx> > Cc: Zhang Rui <rui.zhang@xxxxxxxxx> > Cc: Rafael Wysocki <rafael.j.wysocki@xxxxxxxxx> > Cc: Kristin Jacque <kristin.jacque@xxxxxxxxx> > Cc: Tiffany Kasanicky <tiffany.j.kasanicky@xxxxxxxxx> > Cc: Ryon Jensen <ryon.jensen@xxxxxxxxx> > Reported-by: Anush Seetharaman <anush.seetharaman@xxxxxxxxx> > Fixes: 1c8fce27e275 ("ACPI: introduce drivers/acpi/sysfs.c") > Signed-off-by: Dan Williams <dan.j.williams@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 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 majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
