lkml.org 
[lkml]   [2015]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 3.4 035/176] driver core: Fix unbalanced device reference in drivers_probe
Date
From: Alex Williamson <alex.williamson@redhat.com>

3.4.107-rc1 review patch. If anyone has any objections, please let me know.

------------------


commit bb34cb6bbd287b57e955bc5cfd42fcde6aaca279 upstream.

bus_find_device_by_name() acquires a device reference which is never
released. This results in an object leak, which on older kernels
results in failure to release all resources of PCI devices. libvirt
uses drivers_probe to re-attach devices to the host after assignment
and is therefore a common trigger for this leak.

Example:

# cd /sys/bus/pci/
# dmesg -C
# echo 1 > devices/0000\:01\:00.0/sriov_numvfs
# echo 0 > devices/0000\:01\:00.0/sriov_numvfs
# dmesg | grep 01:10
pci 0000:01:10.0: [8086:10ca] type 00 class 0x020000
kobject: '0000:01:10.0' (ffff8801d79cd0a8): kobject_add_internal: parent: '0000:00:01.0', set: 'devices'
kobject: '0000:01:10.0' (ffff8801d79cd0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79cd0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'
kobject: '0000:01:10.0' (ffff8801d79cd0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79cd0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'
kobject: '0000:01:10.0' (ffff8801d79cd0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79cd0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'
kobject: '0000:01:10.0' (ffff8801d79cd0a8): kobject_cleanup, parent (null)
kobject: '0000:01:10.0' (ffff8801d79cd0a8): calling ktype release
kobject: '0000:01:10.0': free name

[kobject freed as expected]

# dmesg -C
# echo 1 > devices/0000\:01\:00.0/sriov_numvfs
# echo 0000:01:10.0 > drivers_probe
# echo 0 > devices/0000\:01\:00.0/sriov_numvfs
# dmesg | grep 01:10
pci 0000:01:10.0: [8086:10ca] type 00 class 0x020000
kobject: '0000:01:10.0' (ffff8801d79ce0a8): kobject_add_internal: parent: '0000:00:01.0', set: 'devices'
kobject: '0000:01:10.0' (ffff8801d79ce0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79ce0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'
kobject: '0000:01:10.0' (ffff8801d79ce0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79ce0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'
kobject: '0000:01:10.0' (ffff8801d79ce0a8): kobject_uevent_env
kobject: '0000:01:10.0' (ffff8801d79ce0a8): fill_kobj_path: path = '/devices/pci0000:00/0000:00:01.0/0000:01:10.0'

[no free]

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
drivers/base/bus.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index b850cec..0f682f7 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -245,13 +245,15 @@ static ssize_t store_drivers_probe(struct bus_type *bus,
const char *buf, size_t count)
{
struct device *dev;
+ int err = -EINVAL;

dev = bus_find_device_by_name(bus, NULL, buf);
if (!dev)
return -ENODEV;
- if (bus_rescan_devices_helper(dev, NULL) != 0)
- return -EINVAL;
- return count;
+ if (bus_rescan_devices_helper(dev, NULL) == 0)
+ err = count;
+ put_device(dev);
+ return err;
}
#endif

--
1.9.1


\
 
 \ /
  Last update: 2015-04-09 11:21    [W:0.539 / U:1.164 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site