linux-stable.git/drivers/base/bus.c, branch v4.13

driver-core: remove struct bus_type.dev_attrs

2017-06-12T14:18:37+00:00

Now that all in-kernel users of bus_type.dev_attrs have been converted
to use dev_groups instead, the dev_attrs field, and logic surrounding
it, can be removed.

Signed-off-by: Greg Kroah-Hartman

kobject: support passing in variables for synthetic uevents

2017-05-25T16:30:51+00:00

This patch makes it possible to pass additional arguments in addition
to uevent action name when writing /sys/.../uevent attribute. These
additional arguments are then inserted into generated synthetic uevent
as additional environment variables.

Before, we were not able to pass any additional uevent environment
variables for synthetic uevents. This made it hard to identify such uevents
properly in userspace to make proper distinction between genuine uevents
originating from kernel and synthetic uevents triggered from userspace.
Also, it was not possible to pass any additional information which would
make it possible to optimize and change the way the synthetic uevents are
processed back in userspace based on the originating environment of the
triggering action in userspace. With the extra additional variables, we are
able to pass through this extra information needed and also it makes it
possible to synchronize with such synthetic uevents as they can be clearly
identified back in userspace.

The format for writing the uevent attribute is following:

    ACTION [UUID [KEY=VALUE ...]

There's no change in how "ACTION" is recognized - it stays the same
("add", "change", "remove"). The "ACTION" is the only argument required
to generate synthetic uevent, the rest of arguments, that this patch
adds support for, are optional.

The "UUID" is considered as transaction identifier so it's possible to
use the same UUID value for one or more synthetic uevents in which case
we logically group these uevents together for any userspace listeners.
The "UUID" is expected to be in "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
format where "x" is a hex digit. The value appears in uevent as
"SYNTH_UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx" environment variable.

The "KEY=VALUE" pairs can contain alphanumeric characters only. It's
possible to define zero or more more pairs - each pair is then delimited
by a space character " ". Each pair appears in synthetic uevents as
"SYNTH_ARG_KEY=VALUE" environment variable. That means the KEY name gains
"SYNTH_ARG_" prefix to avoid possible collisions with existing variables.
To pass the "KEY=VALUE" pairs, it's also required to pass in the "UUID"
part for the synthetic uevent first.

If "UUID" is not passed in, the generated synthetic uevent gains
"SYNTH_UUID=0" environment variable automatically so it's possible to
identify this situation in userspace when reading generated uevent and so
we can still make a difference between genuine and synthetic uevents.

Signed-off-by: Peter Rajnoha 
Signed-off-by: Greg Kroah-Hartman

driver core: bus: use to_subsys_private and to_device_private_bus

2016-02-10T01:25:27+00:00

Use to_subsys_private() and to_device_private_bus() instead of open-coding.

Signed-off-by: Geliang Tang 
Signed-off-by: Greg Kroah-Hartman

driver core: bus: use list_for_each_entry*

2016-02-10T01:25:27+00:00

Use list_for_each_entry*() instead of list_for_each*() to simplify
the code.

Signed-off-by: Geliang Tang 
Signed-off-by: Greg Kroah-Hartman

driver-core: add asynchronous probing support for drivers

2015-05-20T07:25:24+00:00

Some devices take a long time when initializing, and not all drivers are
suited to initialize their devices when they are open. For example,
input drivers need to interrogate their devices in order to publish
device's capabilities before userspace will open them. When such drivers
are compiled into kernel they may stall entire kernel initialization.

This change allows drivers request for their probe functions to be
called asynchronously during driver and device registration (manual
binding is still synchronous). Because async_schedule is used to perform
asynchronous calls module loading will still wait for the probing to
complete.

Note that the end goal is to make the probing asynchronous by default,
so annotating drivers with PROBE_PREFER_ASYNCHRONOUS is a temporary
measure that allows us to speed up boot process while we validating and
fixing the rest of the drivers and preparing userspace.

This change is based on earlier patch by "Luis R. Rodriguez"


Signed-off-by: Dmitry Torokhov 
Signed-off-by: Greg Kroah-Hartman

driver core: bus: Goto appropriate labels on failure in bus_add_device

2015-03-25T12:40:31+00:00

It is not necessary to call device_remove_groups() when device_add_groups()
fails.

The group added by device_add_groups() should be removed if sysfs_create_link()
fails.

Fixes: fa6fdb33b486 ("driver core: bus_type: add dev_groups")
Signed-off-by: Junjie Mao 
Signed-off-by: Greg Kroah-Hartman

driver core: Fix unbalanced device reference in drivers_probe

2014-11-07T19:17:27+00:00

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 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

Merge branch 'master' into for-next

2014-02-20T13:54:28+00:00

treewide: Fix typo in Documentation/DocBook

2014-02-19T13:58:17+00:00

This patch fix spelling typo in Documentation/DocBook.
It is because .html and .xml files are generated by make htmldocs,
I have to fix a typo within the source files.

Signed-off-by: Masanari Iida 
Acked-by: Randy Dunlap 
Signed-off-by: Jiri Kosina

driver-core: Fix use-after-free triggered by bus_unregister()

2014-01-08T23:36:18+00:00

Avoid that bus_unregister() triggers a use-after-free with
CONFIG_DEBUG_KOBJECT_RELEASE=y. This patch avoids that the
following sequence triggers a kernel crash with memory poisoning
enabled:
* bus_register()
* driver_register()
* driver_unregister()
* bus_unregister()

The above sequence causes the bus private data to be freed from
inside the bus_unregister() call although it is not guaranteed in
that function that the reference count on the bus private data has
dropped to zero. As an example, with CONFIG_DEBUG_KOBJECT_RELEASE=y
the ${bus}/drivers kobject is still holding a reference on
bus->p->subsys.kobj via its parent pointer at the time the bus
private data is freed. Fix this by deferring freeing the bus private
data until the last kobject_put() call on bus->p->subsys.kobj.

The kernel oops triggered by the above sequence and with memory
poisoning enabled and that is fixed by this patch is as follows:

general protection fault: 0000 [#1] PREEMPT SMP
CPU: 3 PID: 2711 Comm: kworker/3:32 Tainted: G        W  O 3.13.0-rc4-debug+ #1
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: events kobject_delayed_cleanup
task: ffff880037f866d0 ti: ffff88003b638000 task.ti: ffff88003b638000
Call Trace:
 [] ? kobject_get_path+0x25/0x100
 [] kobject_uevent_env+0x134/0x600
 [] kobject_uevent+0xb/0x10
 [] kobject_delayed_cleanup+0xc2/0x1b0
 [] process_one_work+0x217/0x700
 [] ? process_one_work+0x1ab/0x700
 [] worker_thread+0x11b/0x3a0
 [] ? process_one_work+0x700/0x700
 [] kthread+0xf0/0x110
 [] ? insert_kthread_work+0x80/0x80
 [] ret_from_fork+0x7c/0xb0
 [] ? insert_kthread_work+0x80/0x80
Code: 89 f8 48 89 e5 f6 82 c0 27 63 81 20 74 15 0f 1f 44 00 00 48 83 c0 01 0f b6 10 f6 82 c0 27 63 81 20 75 f0 5d c3 66 0f 1f 44 00 00 <80> 3f 00 55 48 89 e5 74 15 48 89 f8 0f 1f 40 00 48 83 c0 01 80
RIP  [] strlen+0x0/0x30
 RSP 
---[ end trace 210f883ef80376aa ]---

Signed-off-by: Bart Van Assche 
Acked-by: Ming Lei 
Signed-off-by: Greg Kroah-Hartman