More readable with quote character sorry for the duplicate. Hi Hariprasad, > Hi Kory Maincent. > > On Tue, 26 Mar 2019 at 13:21, Köry Maincent <kory.maincent@xxxxxxxxxxx > <mailto:kory.maincent@xxxxxxxxxxx>> 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. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
