linux-stable.git/drivers/base/dd.c, branch linux-5.4.y

driver core: Release all resources during unbind before updating device links

2023-12-08T07:44:22+00:00

commit 2e84dc37920012b458e9458b19fc4ed33f81bc74 upstream.

This commit fixes a bug in commit 9ed9895370ae ("driver core: Functional
dependencies tracking support") where the device link status was
incorrectly updated in the driver unbind path before all the device's
resources were released.

Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
Cc: stable 
Reported-by: Uwe Kleine-König 
Closes: https://lore.kernel.org/all/20231014161721.f4iqyroddkcyoefo@pengutronix.de/
Signed-off-by: Saravana Kannan 
Cc: Thierry Reding 
Cc: Yang Yingliang 
Cc: Andy Shevchenko 
Cc: Mark Brown 
Cc: Matti Vaittinen 
Cc: James Clark 
Acked-by: "Rafael J. Wysocki" 
Tested-by: Uwe Kleine-König 
Acked-by: Uwe Kleine-König 
Link: https://lore.kernel.org/r/20231018013851.3303928-1-saravanak@google.com
Signed-off-by: Uwe Kleine-König 
Signed-off-by: Greg Kroah-Hartman

driver core: Fix bus_type.match() error handling in __driver_attach()

2023-01-18T10:42:00+00:00

commit 27c0d217340e47ec995557f61423ef415afba987 upstream.

When a driver registers with a bus, it will attempt to match with every
device on the bus through the __driver_attach() function. Currently, if
the bus_type.match() function encounters an error that is not
-EPROBE_DEFER, __driver_attach() will return a negative error code, which
causes the driver registration logic to stop trying to match with the
remaining devices on the bus.

This behavior is not correct; a failure while matching a driver to a
device does not mean that the driver won't be able to match and bind
with other devices on the bus. Update the logic in __driver_attach()
to reflect this.

Fixes: 656b8035b0ee ("ARM: 8524/1: driver cohandle -EPROBE_DEFER from bus_type.match()")
Cc: stable@vger.kernel.org
Cc: Saravana Kannan 
Signed-off-by: Isaac J. Manjarres 
Link: https://lore.kernel.org/r/20220921001414.4046492-1-isaacmanjarres@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: Don't probe devices after bus_type.match() probe deferral

2022-09-15T10:04:52+00:00

commit 25e9fbf0fd38868a429feabc38abebfc6dbf6542 upstream.

Both __device_attach_driver() and __driver_attach() check the return
code of the bus_type.match() function to see if the device needs to be
added to the deferred probe list. After adding the device to the list,
the logic attempts to bind the device to the driver anyway, as if the
device had matched with the driver, which is not correct.

If __device_attach_driver() detects that the device in question is not
ready to match with a driver on the bus, then it doesn't make sense for
the device to attempt to bind with the current driver or continue
attempting to match with any of the other drivers on the bus. So, update
the logic in __device_attach_driver() to reflect this.

If __driver_attach() detects that a driver tried to match with a device
that is not ready to match yet, then the driver should not attempt to bind
with the device. However, the driver can still attempt to match and bind
with other devices on the bus, as drivers can be bound to multiple
devices. So, update the logic in __driver_attach() to reflect this.

Fixes: 656b8035b0ee ("ARM: 8524/1: driver cohandle -EPROBE_DEFER from bus_type.match()")
Cc: stable@vger.kernel.org
Cc: Saravana Kannan 
Reported-by: Guenter Roeck 
Tested-by: Guenter Roeck 
Tested-by: Linus Walleij 
Reviewed-by: Saravana Kannan 
Signed-off-by: Isaac J. Manjarres 
Link: https://lore.kernel.org/r/20220817184026.3468620-1-isaacmanjarres@google.com
Signed-off-by: Greg Kroah-Hartman

driver core: fix potential deadlock in __driver_attach

2022-08-25T09:17:52+00:00

[ Upstream commit 70fe758352cafdee72a7b13bf9db065f9613ced8 ]

In __driver_attach function, There are also AA deadlock problem,
like the commit b232b02bf3c2 ("driver core: fix deadlock in
__device_attach").

stack like commit b232b02bf3c2 ("driver core: fix deadlock in
__device_attach").
list below:
    In __driver_attach function, The lock holding logic is as follows:
    ...
    __driver_attach
    if (driver_allows_async_probing(drv))
      device_lock(dev)      // get lock dev
        async_schedule_dev(__driver_attach_async_helper, dev); // func
          async_schedule_node
            async_schedule_node_domain(func)
              entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
              /* when fail or work limit, sync to execute func, but
                 __driver_attach_async_helper will get lock dev as
                 will, which will lead to A-A deadlock.  */
              if (!entry || atomic_read(&entry_count) > MAX_WORK) {
                func;
              else
                queue_work_node(node, system_unbound_wq, &entry->work)
      device_unlock(dev)

    As above show, when it is allowed to do async probes, because of
    out of memory or work limit, async work is not be allowed, to do
    sync execute instead. it will lead to A-A deadlock because of
    __driver_attach_async_helper getting lock dev.

Reproduce:
and it can be reproduce by make the condition
(if (!entry || atomic_read(&entry_count) > MAX_WORK)) untenable, like
below:

[  370.785650] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables
this message.
[  370.787154] task:swapper/0       state:D stack:    0 pid:    1 ppid:
0 flags:0x00004000
[  370.788865] Call Trace:
[  370.789374]  
[  370.789841]  __schedule+0x482/0x1050
[  370.790613]  schedule+0x92/0x1a0
[  370.791290]  schedule_preempt_disabled+0x2c/0x50
[  370.792256]  __mutex_lock.isra.0+0x757/0xec0
[  370.793158]  __mutex_lock_slowpath+0x1f/0x30
[  370.794079]  mutex_lock+0x50/0x60
[  370.794795]  __device_driver_lock+0x2f/0x70
[  370.795677]  ? driver_probe_device+0xd0/0xd0
[  370.796576]  __driver_attach_async_helper+0x1d/0xd0
[  370.797318]  ? driver_probe_device+0xd0/0xd0
[  370.797957]  async_schedule_node_domain+0xa5/0xc0
[  370.798652]  async_schedule_node+0x19/0x30
[  370.799243]  __driver_attach+0x246/0x290
[  370.799828]  ? driver_allows_async_probing+0xa0/0xa0
[  370.800548]  bus_for_each_dev+0x9d/0x130
[  370.801132]  driver_attach+0x22/0x30
[  370.801666]  bus_add_driver+0x290/0x340
[  370.802246]  driver_register+0x88/0x140
[  370.802817]  ? virtio_scsi_init+0x116/0x116
[  370.803425]  scsi_register_driver+0x1a/0x30
[  370.804057]  init_sd+0x184/0x226
[  370.804533]  do_one_initcall+0x71/0x3a0
[  370.805107]  kernel_init_freeable+0x39a/0x43a
[  370.805759]  ? rest_init+0x150/0x150
[  370.806283]  kernel_init+0x26/0x230
[  370.806799]  ret_from_fork+0x1f/0x30

To fix the deadlock, move the async_schedule_dev outside device_lock,
as we can see, in async_schedule_node_domain, the parameter of
queue_work_node is system_unbound_wq, so it can accept concurrent
operations. which will also not change the code logic, and will
not lead to deadlock.

Fixes: ef0ff68351be ("driver core: Probe devices asynchronously instead of the driver")
Signed-off-by: Zhang Wensheng 
Link: https://lore.kernel.org/r/20220622074327.497102-1-zhangwensheng5@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

driver core: fix deadlock in __device_attach

2022-06-14T16:11:54+00:00

[ Upstream commit b232b02bf3c205b13a26dcec08e53baddd8e59ed ]

In __device_attach function, The lock holding logic is as follows:
...
__device_attach
device_lock(dev)      // get lock dev
  async_schedule_dev(__device_attach_async_helper, dev); // func
    async_schedule_node
      async_schedule_node_domain(func)
        entry = kzalloc(sizeof(struct async_entry), GFP_ATOMIC);
	/* when fail or work limit, sync to execute func, but
	   __device_attach_async_helper will get lock dev as
	   well, which will lead to A-A deadlock.  */
	if (!entry || atomic_read(&entry_count) > MAX_WORK) {
	  func;
	else
	  queue_work_node(node, system_unbound_wq, &entry->work)
  device_unlock(dev)

As shown above, when it is allowed to do async probes, because of
out of memory or work limit, async work is not allowed, to do
sync execute instead. it will lead to A-A deadlock because of
__device_attach_async_helper getting lock dev.

To fix the deadlock, move the async_schedule_dev outside device_lock,
as we can see, in async_schedule_node_domain, the parameter of
queue_work_node is system_unbound_wq, so it can accept concurrent
operations. which will also not change the code logic, and will
not lead to deadlock.

Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers")
Signed-off-by: Zhang Wensheng 
Link: https://lore.kernel.org/r/20220518074516.1225580-1-zhangwensheng5@huawei.com
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

driver core: dd: fix return value of __setup handler

2022-04-15T12:18:20+00:00

[ Upstream commit f2aad54703dbe630f9d8b235eb58e8c8cc78f37d ]

When "driver_async_probe=nulltty" is used on the kernel boot command line,
it causes an Unknown parameter message and the string is added to init's
environment strings, polluting them.

  Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6
  driver_async_probe=nulltty", will be passed to user space.

 Run /sbin/init as init process
   with arguments:
     /sbin/init
   with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc6
     driver_async_probe=nulltty

Change the return value of the __setup function to 1 to indicate
that the __setup option has been handled.

Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Fixes: 1ea61b68d0f8 ("async: Add cmdline option to specify drivers to be async probed")
Cc: Feng Tang 
Cc: Greg Kroah-Hartman 
Cc: "Rafael J. Wysocki" 
Reported-by: Igor Zhbanov 
Reviewed-by: Feng Tang 
Signed-off-by: Randy Dunlap 
Link: https://lore.kernel.org/r/20220301041829.15137-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin

driver core: Fix locking bug in deferred_probe_timeout_work_func()

2021-04-16T09:46:38+00:00

commit eed6e41813deb9ee622cd9242341f21430d7789f upstream.

list_for_each_entry_safe() is only useful if we are deleting nodes in a
linked list within the loop. It doesn't protect against other threads
adding/deleting nodes to the list in parallel. We need to grab
deferred_probe_mutex when traversing the deferred_probe_pending_list.

Cc: stable@vger.kernel.org
Fixes: 25b4e70dcce9 ("driver core: allow stopping deferred probe after init")
Signed-off-by: Saravana Kannan 
Link: https://lore.kernel.org/r/20210402040342.2944858-2-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman

PM: runtime: Resume the device earlier in __device_release_driver()

2020-11-10T11:37:34+00:00

commit 9226c504e364158a17a68ff1fe9d67d266922f50 upstream.

Since the device is resumed from runtime-suspend in
__device_release_driver() anyway, it is better to do that before
looking for busy managed device links from it to consumers, because
if there are any, device_links_unbind_consumers() will be called
and it will cause the consumer devices' drivers to unbind, so the
consumer devices will be runtime-resumed.  In turn, resuming each
consumer device will cause the supplier to be resumed and when the
runtime PM references from the given consumer to it are dropped, it
may be suspended.  Then, the runtime-resume of the next consumer
will cause the supplier to resume again and so on.

Update the code accordingly.

Signed-off-by: Rafael J. Wysocki 
Fixes: 9ed9895370ae ("driver core: Functional dependencies tracking support")
Cc: All applicable  # All applicable
Tested-by: Xiang Chen 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

PM: runtime: Drop pm_runtime_clean_up_links()

2020-11-10T11:37:34+00:00

commit d6e36668598154820177bfd78c1621d8e6c580a2 upstream.

After commit d12544fb2aa9 ("PM: runtime: Remove link state checks in
rpm_get/put_supplier()") nothing prevents the consumer device's
runtime PM from acquiring additional references to the supplier
device after pm_runtime_clean_up_links() has run (or even while it
is running), so calling this function from __device_release_driver()
may be pointless (or even harmful).

Moreover, it ignores stateless device links, so the runtime PM
handling of managed and stateless device links is inconsistent
because of it, so better get rid of it entirely.

Fixes: d12544fb2aa9 ("PM: runtime: Remove link state checks in rpm_get/put_supplier()")
Signed-off-by: Rafael J. Wysocki 
Cc: 5.1+  # 5.1+
Tested-by: Xiang Chen 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

driver core: Fix probe_count imbalance in really_probe()

2020-10-14T08:32:59+00:00

commit b292b50b0efcc7095d8bf15505fba6909bb35dce upstream.

syzbot is reporting hung task in wait_for_device_probe() [1]. At least,
we always need to decrement probe_count if we incremented probe_count in
really_probe().

However, since I can't find "Resources present before probing" message in
the console log, both "this message simply flowed off" and "syzbot is not
hitting this path" will be possible. Therefore, while we are at it, let's
also prepare for concurrent wait_for_device_probe() calls by replacing
wake_up() with wake_up_all().

[1] https://syzkaller.appspot.com/bug?id=25c833f1983c9c1d512f4ff860dd0d7f5a2e2c0f

Reported-by: syzbot 
Fixes: 7c35e699c88bd607 ("driver core: Print device when resources present in really_probe()")
Cc: Geert Uytterhoeven 
Signed-off-by: Tetsuo Handa 
Cc: stable 
Link: https://lore.kernel.org/r/20200713021254.3444-1-penguin-kernel@I-love.SAKURA.ne.jp
[iwamatsu: Drop patch for deferred_probe_timeout_work_func()]
Signed-off-by: Nobuhiro Iwamatsu (CIP) 
Signed-off-by: Greg Kroah-Hartman