On Tue, 2 Dec 2014 10:42:02 -0800 "Paul E. McKenney" <paul...@linux.vnet.ibm.com> wrote:
> I was actually suggesting something a bit different. Instead of bisecting > by release, bisect by code. The procedure is as follows: > > 1. I figure out some reliable way of making RCU allow preemption to > be disabled for some RCU read-side critical sections, but not for > others. I send you the patch, which has rcu_read_lock_test() > as well as rcu_read_lock(). > > 2. You build a kernel without my Kconfig hack, with my patch from > #1 above, and build a kernel with CONFIG_PREEMPT=y (which of > course implies CONFIG_TREE_PREEMPT_RCU=y, given that you are > building without my Kconfig hack). > > 3. You make a list of all the rcu_read_lock() uses in the kernel > (or ask me to provide it). You change the rcu_read_lock() > calls in the first half of this list to rcu_read_lock_test(). > > If the kernel locks up as easily with this change as it did > in a stock CONFIG_PREEMPT=y CONFIG_TREE_PREEMPT_RCU=y kernel, > change half of the remaining rcu_read_lock() calls to > rcu_read_lock_test(). If the kernel is much more resistant > to lockup, change half of the rcu_read_lock_test() calls > back to rcu_read_lock(). Ok Paul, I want to do everything I can to help you debug this. So can you provide me the list you mentioned at point 3 (or tell me how can I get it)? If you guide me through this, I can do whatever you need. Thanks! -- Linux 3.17.0-rc6-00235-gb94d525: Shuffling Zombie Juror http://www.youtube.com/DanielFragaBR http://exchangewar.info Bitcoin: 12H6661yoLDUZaYPdah6urZS5WiXwTAUgL -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/