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

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 drivers/regulator/core.c:2396 _regulator_put Fix this by making lis3lv02d_i2c_resume() mirror the new suspend().

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Linux kernel 安全漏洞

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于即使设备已被运行时挂起处理程序关闭，lis3lv02d_i2c_suspend() 也会调用 lis3lv02d_poweroff()。

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