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Message-ID: <473A8B97.5050909@acm.org>
Date: Tue, 13 Nov 2007 22:45:59 -0700
From: Zan Lynx <zlynx@acm.org>
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To: Andrew Morton <akpm@linux-foundation.org>
CC: Gabriel C <nix.or.die@googlemail.com>, linux-kernel@vger.kernel.org,
       Ulrich Drepper <drepper@redhat.com>, Roland McGrath <roland@redhat.com>
Subject: Re: 2.6.24-rc2-mm1
References: <20071113175906.497a1a6a.akpm@linux-foundation.org>	<473A6E72.60503@googlemail.com> <20071113205544.2a7743b4.akpm@linux-foundation.org>
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Andrew Morton wrote:
[cut]
> hm, that was supposed to shut itself off after 100 messages:
> 
> 	if (unlikely(clone_flags & (CLONE_DETACHED|CLONE_STOPPED))) {
> 		static int __read_mostly count = 100;
> 
> 		if (count && printk_ratelimit()) {
> 			char comm[TASK_COMM_LEN];
> 
> 			count--;
> 			printk(KERN_INFO "fork(): process `%s' used deprecated "
> 					"clone flags 0x%lx\n",
> 				get_task_comm(comm, current),
> 				clone_flags & (CLONE_DETACHED|CLONE_STOPPED));
> 		}
> 	}
> 
> I don't see how you got 151 instances.  I guess I'm having another stupid
> day.

It looks like a simple race, two threads do count-- before doing 
if(count), resulting in an almost infinite loop.  Probably.

atomic_test_and_dec might work.