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Date: Sat, 10 Mar 2012 16:16:08 +0100
From: Borislav Petkov <bp@...en8.de>
To: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Linux 3.3-rc6
On Thu, Mar 08, 2012 at 01:18:32PM -0800, Paul E. McKenney wrote:
> This one, which defines RCU_NONIDLE(): https://lkml.org/lkml/2012/2/3/498
>
> And then the following patch on top of that.
Thanks Paul, almost though. You still need to obfuscate :) the other
printk in the function:
--
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index b185a3294c86..221d117a0b4a 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -568,8 +568,9 @@ static void amd_e400_idle(void)
*/
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
&cpu);
- printk(KERN_INFO "Switch to broadcast mode on CPU%d\n",
- cpu);
+ RCU_NONIDLE(
+ printk(KERN_INFO "Switch to broadcast mode on CPU%d\n", cpu);
+ );
}
clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
--
Then it flies. Otherwise, you get the WARN_ON_ONCE with a bit different
backtrace:
[ 0.028246] System has AMD C1E enabled
[ 0.028398] Switch to broadcast mode on CPU0
[ 0.028416] ------------[ cut here ]------------
[ 0.028421] WARNING: at include/linux/rcupdate.h:269 __atomic_notifier_call_chain+0x4d/0xe9()
[ 0.028423] Hardware name: System Product Name
[ 0.028424] Modules linked in:
[ 0.028427] Pid: 0, comm: swapper/0 Not tainted 3.3.0-rc6-00242-g41657bb1a217 #3
[ 0.028429] Call Trace:
[ 0.028433] [<ffffffff81029d98>] warn_slowpath_common+0x83/0x9b
[ 0.028436] [<ffffffff81029dca>] warn_slowpath_null+0x1a/0x1c
[ 0.028439] [<ffffffff8104ff34>] __atomic_notifier_call_chain+0x4d/0xe9
[ 0.028441] [<ffffffff8104ffe4>] atomic_notifier_call_chain+0x14/0x16
[ 0.028445] [<ffffffff8122c079>] notify_write+0x29/0x2b
[ 0.028447] [<ffffffff8122efbb>] vt_console_print+0x243/0x2fe
[ 0.028450] [<ffffffff8102a039>] __call_console_drivers+0x77/0x89
[ 0.028453] [<ffffffff8102a222>] _call_console_drivers+0x5c/0x60
[ 0.028456] [<ffffffff8102a59a>] console_unlock+0x118/0x212
[ 0.028458] [<ffffffff8102ab4e>] vprintk+0x3be/0x403
[ 0.028461] [<ffffffff813e7dab>] ? _raw_spin_unlock_irqrestore+0x38/0x69
[ 0.028464] [<ffffffff813df4ee>] printk+0x41/0x43
[ 0.028467] [<ffffffff813e7dab>] ? _raw_spin_unlock_irqrestore+0x38/0x69
[ 0.028470] [<ffffffff8105a8ab>] ? local_clock+0xf/0x3b
[ 0.028473] [<ffffffff81009dc6>] amd_e400_idle+0xbb/0xf1
[ 0.028476] [<ffffffff81000801>] cpu_idle+0x6c/0xc8
[ 0.028478] [<ffffffff813cd1d0>] rest_init+0x124/0x12b
[ 0.028480] [<ffffffff813cd116>] ? rest_init+0x6a/0x12b
[ 0.028484] [<ffffffff8185aa18>] start_kernel+0x2d5/0x2e2
[ 0.028486] [<ffffffff8185a26e>] x86_64_start_reservations+0x7e/0x82
[ 0.028489] [<ffffffff8185a362>] x86_64_start_kernel+0xf0/0xf7
[ 0.028494] ---[ end trace 4eaa2a86a8e2da22 ]---
[ 0.028496] ------------[ cut here ]------------
[ 0.028498] WARNING: at include/linux/rcupdate.h:275 __atomic_notifier_call_chain+0xb4/0xe9()
[ 0.028500] Hardware name: System Product Name
[ 0.028501] Modules linked in:
[ 0.028503] Pid: 0, comm: swapper/0 Tainted: G W 3.3.0-rc6-00242-g41657bb1a217 #3
[ 0.028505] Call Trace:
[ 0.028507] [<ffffffff81029d98>] warn_slowpath_common+0x83/0x9b
[ 0.028510] [<ffffffff81029dca>] warn_slowpath_null+0x1a/0x1c
[ 0.028512] [<ffffffff8104ff9b>] __atomic_notifier_call_chain+0xb4/0xe9
[ 0.028515] [<ffffffff8104ff3b>] ? __atomic_notifier_call_chain+0x54/0xe9
[ 0.028517] [<ffffffff8104ffe4>] atomic_notifier_call_chain+0x14/0x16
[ 0.028520] [<ffffffff8122c079>] notify_write+0x29/0x2b
[ 0.028522] [<ffffffff8122efbb>] vt_console_print+0x243/0x2fe
[ 0.028525] [<ffffffff8102a039>] __call_console_drivers+0x77/0x89
[ 0.028527] [<ffffffff8102a222>] _call_console_drivers+0x5c/0x60
[ 0.028530] [<ffffffff8102a59a>] console_unlock+0x118/0x212
[ 0.028532] [<ffffffff8102ab4e>] vprintk+0x3be/0x403
[ 0.028535] [<ffffffff813e7dab>] ? _raw_spin_unlock_irqrestore+0x38/0x69
[ 0.028537] [<ffffffff813df4ee>] printk+0x41/0x43
[ 0.028539] [<ffffffff813e7dab>] ? _raw_spin_unlock_irqrestore+0x38/0x69
[ 0.028542] [<ffffffff8105a8ab>] ? local_clock+0xf/0x3b
[ 0.028544] [<ffffffff81009dc6>] amd_e400_idle+0xbb/0xf1
[ 0.028546] [<ffffffff81000801>] cpu_idle+0x6c/0xc8
[ 0.028548] [<ffffffff813cd1d0>] rest_init+0x124/0x12b
[ 0.028550] [<ffffffff813cd116>] ? rest_init+0x6a/0x12b
[ 0.028553] [<ffffffff8185aa18>] start_kernel+0x2d5/0x2e2
[ 0.028555] [<ffffffff8185a26e>] x86_64_start_reservations+0x7e/0x82
[ 0.028557] [<ffffffff8185a362>] x86_64_start_kernel+0xf0/0xf7
[ 0.028559] ---[ end trace 4eaa2a86a8e2da23 ]---
Thanks.
--
Regards/Gruss,
Boris.
--
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