From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f69.google.com (mail-pa0-f69.google.com [209.85.220.69]) by kanga.kvack.org (Postfix) with ESMTP id 647326B007E for ; Fri, 3 Jun 2016 03:15:56 -0400 (EDT) Received: by mail-pa0-f69.google.com with SMTP id x1so83185737pav.3 for ; Fri, 03 Jun 2016 00:15:56 -0700 (PDT) Received: from mail-pf0-x242.google.com (mail-pf0-x242.google.com. [2607:f8b0:400e:c00::242]) by mx.google.com with ESMTPS id r86si5787937pfb.204.2016.06.03.00.15.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Jun 2016 00:15:55 -0700 (PDT) Received: by mail-pf0-x242.google.com with SMTP id 62so10681106pfd.3 for ; Fri, 03 Jun 2016 00:15:55 -0700 (PDT) Date: Fri, 3 Jun 2016 16:15:51 +0900 From: Sergey Senozhatsky Subject: Re: [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup Message-ID: <20160603071551.GA453@swordfish> References: <20160601131122.7dbb0a65@canb.auug.org.au> <20160602014835.GA635@swordfish> <20160602092113.GH1995@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160602092113.GH1995@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Sergey Senozhatsky , Andrew Morton , Vlastimil Babka , "Kirill A. Shutemov" , Stephen Rothwell , linux-mm@kvack.org, linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Andrea Arcangeli Hello, On (06/02/16 11:21), Michal Hocko wrote: [..] > @@ -2863,6 +2854,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, > > collect_mm_slot(mm_slot); > } > + mmput(mm); > > return progress; > } this possibly sleeping mmput() is called from under the spin_lock(&khugepaged_mm_lock). there is also a trivial build fixup needed (move collect_mm_slot() before __khugepaged_exit()). it's quite hard to trigger the bug (somehow), so I can't follow up with more information as of now. -ss -- 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