Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

misc: lis3lv02d_i2c: Fix regulators getting en-/dis-abled twice on suspend/resume

When not configured for wakeup lis3lv02d_i2c_suspend() will call lis3lv02d_poweroff() even if the device has already been turned off by the runtime-suspend handler and if configured for wakeup and the device is runtime-suspended at this point then it is not turned back on to serve as a wakeup source.

Before commit b1b9f7a49440 ("misc: lis3lv02d_i2c: Add missing setting of the reg_ctrl callback"), lis3lv02d_poweroff() failed to disable the regulators which as a side effect made calling poweroff() twice ok.

Now that poweroff() correctly disables the regulators, doing this twice triggers a WARN() in the regulator core:

unbalanced disables for regulator-dummy WARNING: CPU: 1 PID: 92 at drivers/regulator/core.c:2999 _regulator_disable ...

Fix lis3lv02d_i2c_suspend() to not call poweroff() a second time if already runtime-suspended and add a poweron() call when necessary to make wakeup work.

lis3lv02d_i2c_resume() has similar issues, with an added weirness that it always powers on the device if it is runtime suspended, after which the first runtime-resume will call poweron() again, causing the enabled count for the regulator to increase by 1 every suspend/resume. These unbalanced regulator_enable() calls cause the regulator to never be turned off and trigger the following WARN() on driver unbind:

WARNING: CPU: 1 PID: 1724 at…