[v2] Fix some errors in the devfreq core layer when governor is NULL

[PATCH v2 0/4] Fix some errors in the devfreq core layer when governor is NULL

Yaxiong Tian posted 4 patches 3 hours ago

Diff against v1 v1
Download series mbox

drivers/devfreq/devfreq.c | 57 +++++++++++----------------------------
1 file changed, 16 insertions(+), 41 deletions(-)

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[PATCH v2 0/4] Fix some errors in the devfreq core layer when governor is NULL

Posted by Yaxiong Tian 3 hours ago

While doing some development work with devfreq_add_governor()/
devfreq_remove_governor(), I discovered several bugs caused when
devfreq->governor is NULL. Specifically:

1) A possible null pointer issue in devfreq_add_governor(), caused
by devfreq_remove_governor() setting devfreq->governor to NULL in
certain situations, while devfreq_add_governor() lacks corresponding
checks for devfreq->governor.

2) When operating on governor and available_governors under /sys,
there are also some unexpected errors.

For issue 1, the solution is similar to Jie Zhan's PATCH.
https://lore.kernel.org/linux-pm/20260326123428.800407-6-zhanjie9@hisilicon.com/

The original v1 approach actually changed the original logic, which is incorrect.

See the following patches for details.

change in v2:
1) rebase to  linux-next(20260326) /devfreq-next 
2) remove some code to fix null pointer in patch1
3) add  sysfs_update_group() in patch2


Yaxiong Tian (4):
  PM / devfreq: Fix possible null pointer issue in
    devfreq_add_governor()
  PM / devfreq: Fix available_governors_show() when no governor is set
  PM / devfreq: Fix governor_store() failing when device has no current
    governor
  PM / devfreq: Optimize error return value of governor_show()

 drivers/devfreq/devfreq.c | 57 +++++++++++----------------------------
 1 file changed, 16 insertions(+), 41 deletions(-)

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2.25.1