From: Amit Shah <amit.shah@redhat.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, riel@redhat.com, mingo@kernel.org,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
sbw@mit.edu
Subject: Re: [PATCH tip/core/rcu 1/2] rcu: Parallelize and economize NOCB kthread wakeups
Date: Fri, 22 Aug 2014 23:07:52 +0530 [thread overview]
Message-ID: <20140822173752.GA25807@grmbl.mre> (raw)
In-Reply-To: <20140822171405.GJ16198@grmbl.mre>
On (Fri) 22 Aug 2014 [22:44:05], Amit Shah wrote:
> Hm, found it:
>
> The stall happens in do_initcalls().
>
> pm_sysrq_init() is the function that causes the hang. When I #if 0
> the line
>
> register_sysrq_key('o', &sysrq_poweroff_op);
>
> in pm_sysrq_init(), the boot proceeds normally.
>
> Now what this is, and what relation this has to rcu and that patch in
> particular is next...
... and enabling the following debug options makes the bug disappear:
CONFIG_DEBUG_OBJECTS=y
CONFIG_DEBUG_OBJECTS_SELFTEST=y
CONFIG_DEBUG_OBJECTS_FREE=y
CONFIG_DEBUG_OBJECTS_TIMERS=y
CONFIG_DEBUG_OBJECTS_WORK=y
CONFIG_DEBUG_OBJECTS_RCU_HEAD=y
CONFIG_DEBUG_OBJECTS_PERCPU_COUNTER=y
CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT=1
Anyway, so it looks like a race somewhere in the schedule_work_on()
chain. Not sure how to capture the debug messages there w/o disabling
these debug options. I'll keep trying, though.
Amit
next prev parent reply other threads:[~2014-08-22 17:39 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-07 22:48 [PATCH tip/core/rcu 0/2] Callback-offloading changes for 3.17 Paul E. McKenney
2014-07-11 13:35 ` [PATCH tip/core/rcu 1/2] rcu: Parallelize and economize NOCB kthread wakeups Paul E. McKenney
2014-07-11 13:35 ` [PATCH tip/core/rcu 2/2] rcu: Don't offload callbacks unless specifically requested Paul E. McKenney
2014-07-11 13:47 ` Frederic Weisbecker
2014-07-11 15:28 ` Paul E. McKenney
2014-08-08 8:40 ` [PATCH tip/core/rcu 1/2] rcu: Parallelize and economize NOCB kthread wakeups Amit Shah
2014-08-08 16:25 ` Paul E. McKenney
2014-08-08 17:37 ` Amit Shah
2014-08-08 18:18 ` Paul E. McKenney
2014-08-08 18:34 ` Amit Shah
2014-08-08 21:43 ` Paul E. McKenney
2014-08-08 21:46 ` Paul E. McKenney
2014-08-11 7:13 ` Amit Shah
2014-08-11 16:28 ` Paul E. McKenney
2014-08-11 19:41 ` Amit Shah
2014-08-11 20:11 ` Paul E. McKenney
2014-08-11 20:18 ` Amit Shah
2014-08-11 20:34 ` Paul E. McKenney
2014-08-12 3:45 ` Paul E. McKenney
2014-08-12 5:33 ` Amit Shah
2014-08-12 16:06 ` Paul E. McKenney
2014-08-12 21:39 ` Paul E. McKenney
2014-08-12 21:41 ` Paul E. McKenney
2014-08-12 21:44 ` Paul E. McKenney
2014-08-13 5:44 ` Amit Shah
2014-08-13 13:00 ` Paul E. McKenney
2014-08-13 14:18 ` Paul E. McKenney
2014-08-15 5:24 ` Amit Shah
2014-08-15 15:04 ` Paul E. McKenney
2014-08-18 17:53 ` Amit Shah
2014-08-19 4:01 ` Paul E. McKenney
2014-08-22 12:24 ` Amit Shah
2014-08-22 12:36 ` Amit Shah
2014-08-22 12:56 ` Amit Shah
2014-08-22 14:48 ` Paul E. McKenney
2014-08-22 17:14 ` Amit Shah
2014-08-22 17:37 ` Amit Shah [this message]
2014-08-22 21:53 ` Paul E. McKenney
2014-08-22 21:57 ` Paul E. McKenney
2014-08-22 14:43 ` Paul E. McKenney
2014-08-12 5:27 ` Amit Shah
2014-08-12 16:08 ` Paul E. McKenney
-- strict thread matches above, loose matches on Subject: below --
2014-08-23 7:43 Pranith Kumar
2014-08-23 16:51 ` Paul E. McKenney
2014-08-24 0:26 ` Pranith Kumar
2014-08-24 3:23 ` Paul E. McKenney
2014-08-24 3:39 ` Pranith Kumar
2014-08-24 14:36 ` Paul E. McKenney
2014-08-27 4:43 ` Amit Shah
2014-08-27 16:21 ` Paul E. McKenney
2014-08-27 16:43 ` Pranith Kumar
2014-08-27 17:08 ` Paul E. McKenney
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