> -----Original Message----- > From: Akinobu Mita [mailto:akinobu.m...@gmail.com] > Sent: Monday, April 18, 2016 9:02 PM > To: Qianyu Gong <qianyu.g...@nxp.com> > Cc: alexandre.bell...@free-electrons.com; Mingkai Hu <mingkai...@nxp.com>; > rtc-li...@googlegroups.com; linux-kernel@vger.kernel.org > Subject: Re: rtc ds3232 call trace in kernel > > 2016-04-18 15:15 GMT+09:00 Qianyu Gong <qianyu.g...@nxp.com>: > > Hi Akinobu, > > > > > > > > I got an rtc call trace when booting 4.6 kernel on our board and I > > found it > > > > was caused by this patch: > > > > > > > > commit fc1dcb0b39dbb10d3290f2fcd6e154670f699166 > > > > Author: Akinobu Mita <akinobu.m...@gmail.com> > > > > Date: Mon Mar 7 00:27:53 2016 +0900 > > > > > > > > rtc: ds3232: use rtc->ops_lock to protect alarm operations > > > > > > > > ds3232->mutex is used to protect for alarm operations which > > > > need to access status and control registers. > > > > > > > > But we can use rtc->ops_lock instead. rtc->ops_lock is held when > > most > > > > of rtc_class_ops methods are called, so we only need to explicitly > > > > acquire it from irq handler in order to protect form concurrent > > > > accesses. > > > > > > > > Signed-off-by: Akinobu Mita <akinobu.m...@gmail.com> > > > > Signed-off-by: Alexandre Belloni <alexandre.bell...@free-electrons.com > > > > > > > > The problem is that rtc->ops_lock would be accessed in ds3232_irq() > > > > without being initialized as rtc_device_register() is called too late. > > You have already identified the root cause of this issue. > > > As I’m not familiar with rtc things, could I just revert the patch or > > you already > > > > have a solution to this problem? Thanks in advance. > > Could you check if the problem is resolved by moving the call of > devm_rtc_device_register() from the end of ds3232_probe() to just before > registering irq handler?
Yes. It works(no call trace now). Regards, Qianyu
