On Tue, 2012-09-25 at 09:14 +0100, Linus Walleij wrote:
On Mon, Sep 24, 2012 at 11:08 AM, Jon Medhurst (Tixy) tixy@linaro.org wrote:
On Mon, 2012-09-24 at 09:37 +0200, Linus Walleij wrote:
- Drilled into the RCU lockup. With some help from Paul McKenney we got a task dump from CPU0 (the CPU that is locking) but not much more - only the swapper thread is running there and we need to dump its stack.
Quite probably unrelated, but I've seen an RCU lockup on vexpress TC2... https://bugs.launchpad.net/linaro-landing-team-arm/+bug/1051993
Actually it looks related.
Both lockups are triggered by cpuidle and I also have an indication from John Stultz who has seen the same lockup (not clear which system). This is how it looks to me: http://marc.info/?l=linux-kernel&m=134753979619804&w=2
It appears the rate of triggering is system-dependent, possibly this even affects x86 they just haven't seen it because of ... something. So Vexpress seems to see even more of it.
Pawel have you seen the RCU lockups on the v3.6 kernels on your boards?
No, not RCU lockups, however some of my colleagues had some problems originating at twd_handler, similarly to your callstack. Apparently reverting commit 1e75fa8be9fb61e1af46b5b3b176347a4c958ca1 "time: Condense timekeeper.xtime into xtime_sec" helped.
Paweł