linux-stable.git/drivers/devfreq/devfreq.c, branch linux-4.9.y

PM / devfreq: Check NULL governor in available_governors_show

2020-01-12T10:24:15+00:00

commit d68adc8f85cd757bd33c8d7b2660ad6f16f7f3dc upstream.

The governor is initialized after sysfs attributes become visible so in
theory the governor field can be NULL here.

Fixes: bcf23c79c4e46 ("PM / devfreq: Fix available_governor sysfs")
Signed-off-by: Leonard Crestez 
Reviewed-by: Matthias Kaehlcke 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Don't fail devfreq_dev_release if not in list

2020-01-12T10:24:09+00:00

[ Upstream commit 42a6b25e67df6ee6675e8d1eaf18065bd73328ba ]

Right now devfreq_dev_release will print a warning and abort the rest of
the cleanup if the devfreq instance is not part of the global
devfreq_list. But this is a valid scenario, for example it can happen if
the governor can't be found or on any other init error that happens
after device_register.

Initialize devfreq->node to an empty list head in devfreq_add_device so
that list_del becomes a safe noop inside devfreq_dev_release and we can
continue the rest of the cleanup.

Signed-off-by: Leonard Crestez 
Reviewed-by: Matthias Kaehlcke 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Sasha Levin

PM / devfreq: Lock devfreq in trans_stat_show

2019-12-21T09:42:05+00:00

commit 2abb0d5268ae7b5ddf82099b1f8d5aa8414637d4 upstream.

There is no locking in this sysfs show function so stats printing can
race with a devfreq_update_status called as part of freq switching or
with initialization.

Also add an assert in devfreq_update_status to make it clear that lock
must be held by caller.

Fixes: 39688ce6facd ("PM / devfreq: account suspend/resume for stats")
Cc: stable@vger.kernel.org
Signed-off-by: Leonard Crestez 
Reviewed-by: Matthias Kaehlcke 
Reviewed-by: Chanwoo Choi 
Signed-off-by: Chanwoo Choi 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix potential NULL pointer dereference in governor_store

2018-04-13T17:48:09+00:00

[ Upstream commit 63f1e05f7fe9ca509c60154d6a833abf96eecdc9 ]

df->governor is being dereferenced before it is null checked,
hence there is a potential null pointer dereference.

Notice that df->governor is being null checked at line 1004:
if (df->governor) {, which implies it might be null.

Fix this by null checking df->governor before dereferencing it.

Addresses-Coverity-ID: 1401988 ("Dereference before null check")
Fixes: bcf23c79c4e4 ("PM / devfreq: Fix available_governor sysfs")
Signed-off-by: Gustavo A. R. Silva 
Reviewed-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Propagate error from devfreq_add_device()

2018-02-22T14:43:52+00:00

commit d1bf2d30728f310f72296b54f0651ecdb09cbb12 upstream.

Propagate the error of devfreq_add_device() in devm_devfreq_add_device()
rather than statically returning ENOMEM. This makes it slightly faster
to pinpoint the cause of a returned error.

Fixes: 8cd84092d35e ("PM / devfreq: Add resource-managed function for devfreq device")
Cc: stable@vger.kernel.org
Acked-by: Chanwoo Choi 
Signed-off-by: Bjorn Andersson 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix memory leak when fail to register device

2017-09-27T12:39:24+00:00

commit 9e14de1077e9c34f141cf98bdba60cdd5193d962 upstream.

When the devfreq_add_device fails to register deivce, the memory
leak of devfreq instance happen. So, this patch fix the memory
leak issue. Before freeing the devfreq instance checks whether
devfreq instance is NULL or not because the device_unregister()
frees the devfreq instance when jumping to the 'err_init'.
It is to prevent the duplicate the kfee(devfreq).

Fixes: ac4b281176a5 ("PM / devfreq: fix duplicated kfree on devfreq pointer")
Signed-off-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix wrong trans_stat of passive devfreq device

2017-03-12T05:41:44+00:00

commit 30582c25a4b4e0a5e456a309fde79b845e9473b2 upstream.

Until now, the trans_stat information of passive devfreq is not updated.
This patch updates the trans_stat information after setting the target
frequency of passive devfreq device.

Fixes: 996133119f57 ("PM / devfreq: Add new passive governor")
Signed-off-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix available_governor sysfs

2017-03-12T05:41:44+00:00

commit bcf23c79c4e46130701370af4383b61a3cba755c upstream.

The devfreq using passive governor is not able to change the governor.
So, the user can not change the governor through 'available_governor' sysfs
entry. Also, the devfreq which don't use the passive governor is not able to
change to 'passive' governor on the fly.

Fixes: 996133119f57 ("PM / devfreq: Add new passive governor")
Signed-off-by: Chanwoo Choi 
Signed-off-by: MyungJoo Ham 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Fix the bug of devfreq_add_device when governor is NULL

2017-01-26T07:24:44+00:00

commit 73613b16cb5c5d5a659fc8832eff99eead3f9afb upstream.

This patch fixes the bug of devfreq_add_device(). The devfreq device must
have the default governor. If find_devfreq_governor() returns error,
devfreq_add_device() fail to add the devfreq instance.

Fixes: 1b5c1be2c88e (PM / devfreq: map devfreq drivers to governor using name)
Signed-off-by: Chanwoo Choi 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

PM / devfreq: Skip status update on uninitialized previous_freq

2016-10-10T22:01:20+00:00

In case devfreq->previous_freq is still uninitialized in
devfreq_update_status(), i.e. it has value '0', the lookups in
that function fail, eventually leading to some error message:
[    3.041292] devfreq bus_dmc: Couldn't update frequency transition information.

Just skip the statup update in this situation.

Signed-off-by: Tobias Jakobi 
Acked-by: MyungJoo Ham 
Signed-off-by: Rafael J. Wysocki