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Message-ID: <18615.42728.498883.440973@notabene.brown>
Date: Fri, 29 Aug 2008 17:36:08 +1000
From: Neil Brown <neilb@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Jens Axboe <jens.axboe@...cle.com>,
"Rafael J. Wysocki" <rjw@...k.pl>, jurriaan <thunder7@...all.nl>,
linux-kernel@...r.kernel.org
Subject: Re: 2.6.27-rc4: lots of 'in_atomic():1, irqs_disabled():0' with
software-raid1
On Thursday August 28, akpm@...ux-foundation.org wrote:
>
> I'm curious about how this happened.
>
> afaict from reading the code, this:
>
> rcu_read_lock();
> might_sleep();
> rcu_read_unlock();
>
> will warn if CONFIG_PREEMPT_RCU=n but won't warn if
> CONFIG_PREEMPT_RCU=y. If correct, that's a nasty trap.
>
> Is that what you did?
Uhm..
$ grep PREEMPT /home/src/md-x86-64/.config
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
$ grep DEBUG_SPIN /home/src/md-x86-64/.config
CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_SPINLOCK_SLEEP=y
$ grep RCU /home/src/md-x86-64/.config
CONFIG_CLASSIC_RCU=y
# CONFIG_RCU_TORTURE_TEST is not set
This definitely doesn't report an error if I put "might_sleep" inside
rcu_read_lock. I tried to figure out why but got lost.
BTW, I need the following to get current -git to compile.
NeilBrown
Author: NeilBrown <neilb@...e.de>
Date: Tue Aug 19 11:59:37 2008 +1000
Fix compile error in security
diff --git a/include/linux/security.h b/include/linux/security.h
index 2ee5ecf..0cc23a1 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1757,7 +1757,7 @@ static inline int security_ptrace_may_access(struct task_struct *child,
static inline int security_ptrace_traceme(struct task_struct *child)
{
- return cap_ptrace_traceme(parent);
+ return cap_ptrace_traceme(child);
}
static inline int security_capget(struct task_struct *target,
--
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