From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 918C96B004F for ; Tue, 7 Jul 2009 09:21:54 -0400 (EDT) Subject: Re: kmemleak not tainted From: Catalin Marinas In-Reply-To: <20090707131725.GB3238@localdomain.by> References: <20090707115128.GA3238@localdomain.by> <1246970859.9451.34.camel@pc1117.cambridge.arm.com> <20090707131725.GB3238@localdomain.by> Content-Type: text/plain Date: Tue, 07 Jul 2009 14:22:21 +0100 Message-Id: <1246972941.9451.44.camel@pc1117.cambridge.arm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Sergey Senozhatsky Cc: Pekka Enberg , Ingo Molnar , "Paul E. McKenney" , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Tue, 2009-07-07 at 16:17 +0300, Sergey Senozhatsky wrote: > > On Tue, 2009-07-07 at 14:51 +0300, Sergey Senozhatsky wrote: > > > kernel: [ 1917.133154] INFO: RCU detected CPU 0 stall (t=485140/3000 jiffies) [...] > > What I think happens is that the kmemleak thread runs for several > > seconds for scanning the memory and there may not be any context > > switches. I have a patch to add more cond_resched() calls throughout the > > kmemleak_scan() function which I hope will get merged. [...] > > I don't get any of these messages with CONFIG_PREEMPT enabled. > > It started with rc2-git1 (may be). Almost every scan ends with RCU pending. Should I assume that CONFIG_PREEMPT is disabled on your system? The branch with the pending kmemleak patches is below (I sent Linus a pull request): http://www.linux-arm.org/git?p=linux-2.6.git;a=shortlog;h=kmemleak You can try the "Add more cond_resched() calls..." patch and see if it makes any difference. > Hm.. Something is broken... > cat /.../kmemleak > [ 7933.537868] ================================================ > [ 7933.537873] [ BUG: lock held when returning to user space! ] > [ 7933.537876] ------------------------------------------------ > [ 7933.537880] cat/2897 is leaving the kernel with locks still held! > [ 7933.537884] 1 lock held by cat/2897: > [ 7933.537887] #0: (scan_mutex){+.+.+.}, at: [] kmemleak_open+0x4c/0x80 That the "Do not acquire scan_mutex in kmemleak_open()" patch in the same branch. -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org