Messages in this thread | | | Date | Tue, 25 Aug 2009 10:11:36 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH -tip 0/2] Temporary RCU fixes for notrace and hotplug CPU |
| |
On Tue, Aug 25, 2009 at 12:25:49PM -0400, Mathieu Desnoyers wrote: > * Paul E. McKenney (paulmck@linux.vnet.ibm.com) wrote: > > On Tue, Aug 25, 2009 at 10:00:47AM +0200, Ingo Molnar wrote: > > > > > > btw., i'm still seeing crashes with the latest RCU bits: > > > > > > [ 20.621740] Testing event sys_enter_futex: OK > > > [ 20.629738] Testing event sys_exit_futex: OK > > > [ 20.637737] Testing event lock_acquire: [reboot] > > > > > > Possibly due to infinite recursion as well. Config attached. > > > > Color me confused... > > > > Unless someone has a better idea, I will send in a patch that adds > > "notrace" to every RCU API member used by any file in the kernel > > that has "trace" in its name (excluding ptrace.c and rcutree_trace.c, > > of course). This list is as follows: > > > > call_rcu() > > call_rcu_sched() > > rcu_read_lock() > > rcu_read_unlock() > > > > So, any better ideas? > > Tracers using RCU should use the _notrace() version of read_lock/unlock. > I think the callers should be fixed rather than RCU. > > Tracepoints have been designed to use the _notrace variant on the > instrumentation site. The core of tracepoint management use > call_rcu_sched(), which can be traced without any problem. > > I have not followed the late tracing development as closely though, so > errors might have crept in.
Or I might have inadvertently broken something in a non-obvious (to me, anyway) manner.
So, would you be willing to look at commit bc33f24bd in the -tip tree and see if there is anything I broke other than the now-fixed rcu_read_lock_sched_notrace() and rcu_read_unlock_sched_notrace()? And for that matter, whether my alleged fix for these two API members really does fix the problem (-tip commit 7c614d6461)?
The -tip tree is at:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git
And these patches are on the tip/core/rcu branch.
Thanx, Paul
| |