Hi Hariprasad, On 28/03/2019 19:24, hariprasad kelam wrote: Hi Kory Maincent.
On Tue, 26 Mar 2019 at 13:21, Köry Maincent <[email protected]<mailto:[email protected]>> wrote: Hello, I got a kernel warning on the reboot of my embedded board, and sometimes I got stuck in the reboot. I work on the IMX6Q with a PMIC da9063 and the last kernel release. It happens in the da9063_wdt_restart function at the regmap_write call in the CONTROL_F register. (drivers/watchdog/da9063_wdt.c) From trace we are able figure out the flow, reboot | | invokes system call(sys_reboot) | | watchdog_restart)notifier | | da9063_wdt_restart | | It sending I2c rear/write commands. Is this expected behaviour ?? Yes it is. If I access to other register in that function, I don't have this issue. The reason could be ,you are accessing other registers directly not through I2C. I was wrong on this point, because of bad order debug printing in the drivers. I manage to avoid the issue with a hotfix : adding rcu_read_unlock(); before I2C writing in the da9063_wdt_restart function. There is no more koops warning neither freezing reboot. I don't think it is a clean patch and I don't understand the relation to preemption. It may happens because of an RCU critical section not closed? Regards, Kory
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