Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:i2c: stm32f7: Do not prepare/unprepare clock during runtime suspend/resumeIn case there is any sort of clock controller attached to this I2C buscontroller, for example Versaclock or even an AIC32x4 I2C codec, thenan I2C transfer triggered from the clock controller clk_ops .preparecallback may trigger a deadlock on drivers/clk/clk.c prepare_lock mutex.This is because the clock controller first grabs the prepare_lock mutexand then performs the prepare operation, including its I2C access. TheI2C access resumes this I2C bus controller via .runtime_resume callback,which calls clk_prepare_enable(), which attempts to grab the prepare_lockmutex again and deadlocks.Since the clock are already prepared since probe() and unprepared inremove(), use simple clk_enable()/clk_disable() calls to enable anddisable the clock on runtime suspend and resume, to avoid hitting theprepare_lock mutex.
No PoCs from references.
- https://github.com/w4zu/Debian_security