From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
linux-next@vger.kernel.org,
ppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-kernel@vger.kernel.org
Subject: Re: linux-next: boot failure after merge of the final tree (tip related)
Date: Thu, 15 Apr 2010 16:48:30 +1000 [thread overview]
Message-ID: <1271314110.13059.159.camel@pasglop> (raw)
In-Reply-To: <20100415161214.04637496.sfr@canb.auug.org.au>
On Thu, 2010-04-15 at 16:12 +1000, Stephen Rothwell wrote:
>
> Caused by commit bd6d29c25bb1a24a4c160ec5de43e0004e01f72b ("lockstat:
> Make lockstat counting per cpu"). This added a WARN_ON_ONCE to
> debug_atomic_inc() which is called from trace_hardirqs_on_caller()
> with
> irqs enabled.
>
> Line 2301 is:
>
> if (unlikely(curr->hardirqs_enabled)) {
> debug_atomic_inc(redundant_hardirqs_on); <--- 2301
> return;
> }
>
> This is especially bad since on PowerPC, WARN_ON is a TRAP and the
> return
> path from the TRAP also calls trace_hardirqs_on_caller(), so the TRAP
> recurses ...
I think this is because our syscall entry pretty much force-enable irqs.
I remember deciding back then that getting lockdep balanced in that area
was tricky and I didn't do it to avoid adding more overhead to the
syscall path but I suppose I could revisit if necessary.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
linux-kernel@vger.kernel.org, linux-next@vger.kernel.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
ppc-dev <linuxppc-dev@lists.ozlabs.org>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: linux-next: boot failure after merge of the final tree (tip related)
Date: Thu, 15 Apr 2010 16:48:30 +1000 [thread overview]
Message-ID: <1271314110.13059.159.camel@pasglop> (raw)
In-Reply-To: <20100415161214.04637496.sfr@canb.auug.org.au>
On Thu, 2010-04-15 at 16:12 +1000, Stephen Rothwell wrote:
>
> Caused by commit bd6d29c25bb1a24a4c160ec5de43e0004e01f72b ("lockstat:
> Make lockstat counting per cpu"). This added a WARN_ON_ONCE to
> debug_atomic_inc() which is called from trace_hardirqs_on_caller()
> with
> irqs enabled.
>
> Line 2301 is:
>
> if (unlikely(curr->hardirqs_enabled)) {
> debug_atomic_inc(redundant_hardirqs_on); <--- 2301
> return;
> }
>
> This is especially bad since on PowerPC, WARN_ON is a TRAP and the
> return
> path from the TRAP also calls trace_hardirqs_on_caller(), so the TRAP
> recurses ...
I think this is because our syscall entry pretty much force-enable irqs.
I remember deciding back then that getting lockdep balanced in that area
was tricky and I didn't do it to avoid adding more overhead to the
syscall path but I suppose I could revisit if necessary.
Cheers,
Ben.
next prev parent reply other threads:[~2010-04-15 6:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 6:12 linux-next: boot failure after merge of the final tree (tip related) Stephen Rothwell
2010-04-15 6:12 ` Stephen Rothwell
2010-04-15 6:48 ` Benjamin Herrenschmidt [this message]
2010-04-15 6:48 ` Benjamin Herrenschmidt
2010-04-15 6:49 ` linux-next: PowerPC WARN_ON_ONCE() " Ingo Molnar
2010-04-15 6:49 ` Ingo Molnar
2010-04-15 6:55 ` David Miller
2010-04-15 6:55 ` David Miller
2010-04-15 7:32 ` Ingo Molnar
2010-04-15 7:32 ` Ingo Molnar
2010-04-16 1:51 ` Benjamin Herrenschmidt
2010-04-16 1:51 ` Benjamin Herrenschmidt
2010-04-16 1:56 ` Benjamin Herrenschmidt
2010-04-16 1:56 ` Benjamin Herrenschmidt
2010-04-15 10:04 ` Stephen Rothwell
2010-04-15 10:04 ` Stephen Rothwell
2010-04-15 13:37 ` [PATCH] lockdep: Fix redundant_hardirqs_on incremented with irqs enabled Frederic Weisbecker
2010-04-27 7:32 ` Stephen Rothwell
2010-04-27 18:07 ` Frederic Weisbecker
2010-04-28 7:12 ` Stephen Rothwell
2010-04-15 13:00 ` linux-next: PowerPC WARN_ON_ONCE() after merge of the final tree (tip related) Frederic Weisbecker
2010-04-15 13:00 ` Frederic Weisbecker
2010-04-15 14:03 ` Ingo Molnar
2010-04-15 14:03 ` Ingo Molnar
2010-04-15 17:15 ` Frederic Weisbecker
2010-04-15 17:15 ` Frederic Weisbecker
2010-04-16 10:38 ` Peter Zijlstra
2010-04-16 10:38 ` Peter Zijlstra
2010-04-16 12:32 ` Frederic Weisbecker
2010-04-16 12:32 ` Frederic Weisbecker
2010-04-15 17:24 ` Frederic Weisbecker
2010-04-15 17:24 ` Frederic Weisbecker
2010-04-15 17:39 ` Ingo Molnar
2010-04-15 17:39 ` Ingo Molnar
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