On Fri, 23 Sep 2016 10:04:31 +0800 Jisheng Zhang <[email protected]> wrote:
> Hi Thomas, > > On Thu, 22 Sep 2016 15:58:03 +0200 Thomas Gleixner wrote: > > > On Thu, 22 Sep 2016, Jisheng Zhang wrote: > > > > > Currently ti-32k can be used as a scheduler clock. We properly marked > > > omap_32k_read_sched_clock() as notrace but we then call another > > > function ti_32k_read_cycles() that _wasn't_ notrace. > > > > > > Having a traceable function in the sched_clock() path leads to a > > > recursion within ftrace and a kernel crash. > > > > Kernel crash? Doesn't ftrace core prevent recursion? > > a recent similar issue: > > http://www.spinics.net/lists/arm-kernel/msg533480.html Right. But Thomas brought up recursion detection. And I said that would be the fix, but now thinking about it, I've updated the recursion protection so that timer issues should not cause a crash. I'd like to know more, as this appears to be mostly arm related. -- Steve
