linux.git/drivers/base/core.c, branch v4.14.124

kobject: return error code if writing /sys/.../uevent fails

2019-02-12T18:46:02+00:00

[ Upstream commit df44b479654f62b478c18ee4d8bc4e9f897a9844 ]

Propagate error code back to userspace if writing the /sys/.../uevent
file fails. Before, the write operation always returned with success,
even if we failed to recognize the input string or if we failed to
generate the uevent itself.

With the error codes properly propagated back to userspace, we are
able to react in userspace accordingly by not assuming and awaiting
a uevent that is not delivered.

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

drivers: core: Remove glue dirs from sysfs earlier

2019-02-06T16:31:37+00:00

commit 726e41097920a73e4c7c33385dcc0debb1281e18 upstream.

For devices with a class, we create a "glue" directory between
the parent device and the new device with the class name.

This directory is never "explicitely" removed when empty however,
this is left to the implicit sysfs removal done by kobject_release()
when the object loses its last reference via kobject_put().

This is problematic because as long as it's not been removed from
sysfs, it is still present in the class kset and in sysfs directory
structure.

The presence in the class kset exposes a use after free bug fixed
by the previous patch, but the presence in sysfs means that until
the kobject is released, which can take a while (especially with
kobject debugging), any attempt at re-creating such as binding a
new device for that class/parent pair, will result in a sysfs
duplicate file name error.

This fixes it by instead doing an explicit kobject_del() when
the glue dir is empty, by keeping track of the number of
child devices of the gluedir.

This is made easy by the fact that all glue dir operations are
done with a global mutex, and there's already a function
(cleanup_glue_dir) called in all the right places taking that
mutex that can be enhanced for this. It appears that this was
in fact the intent of the function, but the implementation was
wrong.

Signed-off-by: Benjamin Herrenschmidt 
Acked-by: Linus Torvalds 
Cc: Guenter Roeck 
Cc: Zubin Mithra 
Signed-off-by: Greg Kroah-Hartman

driver core: Move device_links_purge() after bus_remove_device()

2018-12-01T08:42:59+00:00

commit 2ec16150179888b81717d1d3ce84e634f4736af2 upstream.

The current ordering of code in device_del() triggers a WARN_ON()
in device_links_purge(), because of an unexpected link status.

The device_links_unbind_consumers() call in device_release_driver()
has to take place before device_links_purge() for the status of all
links to be correct, so move the device_links_purge() call in
device_del() after the invocation of bus_remove_device() which calls
device_release_driver().

Fixes: 9ed9895370ae (driver core: Functional dependencies tracking support)
Signed-off-by: Jeffy Chen 
Reviewed-by: Rafael J. Wysocki 
Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

drivers/base: stop new probing during shutdown

2018-09-26T06:38:04+00:00

[ Upstream commit 3297c8fc65af5d40501ea7cddff1b195cae57e4e ]

There is a race window in device_shutdown(), which may cause
-1. parent device shut down before child or
-2. no shutdown on a new probing device.

For 1st, taking the following scenario:
         device_shutdown                        new plugin device
  list_del_init(parent_dev);
  spin_unlock(list_lock);
                                                  device_add(child)
                                                  probe child
  shutdown parent_dev
       --> now child is on the tail of devices_kset

For 2nd, taking the following scenario:
         device_shutdown                        new plugin device
                                                  device_add(dev)
  device_lock(dev);
  ...
  device_unlock(dev);
                                                  probe dev
       --> now, the new occurred dev has no opportunity to shutdown

To fix this race issue, just prevent the new probing request. With this
logic, device_shutdown() is more similar to dpm_prepare().

Signed-off-by: Pingfan Liu 
Reviewed-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PM / core: Fix supplier device runtime PM usage counter imbalance

2018-07-03T09:24:47+00:00

commit 47e5abfb546a3ace23a77453dc2e9db92704c5ac upstream.

If a device link is added via device_link_add() by the driver of the
link's consumer device, the supplier's runtime PM usage counter is
going to be dropped by the pm_runtime_put_suppliers() call in
driver_probe_device().  However, in that case it is not incremented
unless the supplier driver is already present and the link is not
stateless.  That leads to a runtime PM usage counter imbalance for
the supplier device in a few cases.

To prevent that from happening, bump up the supplier runtime
PM usage counter in device_link_add() for all links with the
DL_FLAG_PM_RUNTIME flag set that are added at the consumer probe
time.  Use pm_runtime_get_noresume() for that as the callers of
device_link_add() who want the supplier to be resumed by it are
expected to pass DL_FLAG_RPM_ACTIVE in flags to it anyway, but
additionally resume the supplier if the link is added during
consumer driver probe to retain the existing behavior for the
callers depending on it.

Fixes: 21d5c57b3726 (PM / runtime: Use device links)
Reported-by: Ulf Hansson 
Reviewed-by: Ulf Hansson 
Tested-by: Marek Szyprowski 
Cc: 4.10+  # 4.10+
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

driver core: Don't ignore class_dir_create_and_add() failure.

2018-06-26T00:06:29+00:00

commit 84d0c27d6233a9ba0578b20f5a09701eb66cee42 upstream.

syzbot is hitting WARN() at kernfs_add_one() [1].
This is because kernfs_create_link() is confused by previous device_add()
call which continued without setting dev->kobj.parent field when
get_device_parent() failed by memory allocation fault injection.
Fix this by propagating the error from class_dir_create_and_add() to
the calllers of get_device_parent().

[1] https://syzkaller.appspot.com/bug?id=fae0fb607989ea744526d1c082a5b8de6529116f

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Cc: Greg Kroah-Hartman 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

PM / runtime: Update links_count also if !CONFIG_SRCU

2018-02-22T14:42:20+00:00

commit 433986c2c265d106d6a8e88006e0131fefc92b7b upstream.

Commit baa8809f6097 (PM / runtime: Optimize the use of device links)
added an invocation of pm_runtime_drop_link() to __device_link_del().
However there are two variants of that function, one for CONFIG_SRCU and
another for !CONFIG_SRCU, and the commit only modified the former.

Fixes: baa8809f6097 (PM / runtime: Optimize the use of device links)
Cc: v4.10+  # v4.10+
Signed-off-by: Lukas Wunner 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

Do not disable driver and bus shutdown hook when class shutdown hook is set.

2017-08-28T16:02:46+00:00

As seen from the implementation of the single class shutdown hook this
is not very sound design.

Rename the class shutdown hook to shutdown_pre to make it clear it runs
before the driver shutdown hook.

Signed-off-by: Michal Suchanek 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'bind_unbind' into driver-core-next

2017-07-22T10:00:15+00:00

This merges the bind_unbind driver core feature into the
driver-core-next branch.  bind_unbind is a branch so that others can
pull and work off of it safely.

Signed-off-by: Greg Kroah-Hartman

driver core: add devm_device_add_group() and friends

2017-07-22T09:59:23+00:00

Many drivers create additional driver-specific device attributes when
binding to the device, and providing managed version of
device_create_group() will simplify unbinding and error handling in probe
path for such drivers.

Without managed version driver writers either have to mix manual and
managed resources, which is prone to errors, or open-code this function by
providing a wrapper to device_add_group() and use it with devm_add_action()
or devm_add_action_or_reset().

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