From: Yongqiang Yang Subject: Re: 3.2.0-rc5 NULL dereference BUG Date: Thu, 5 Jan 2012 10:23:13 +0800 Message-ID: References: <20111218055359.GA17182@localhost> <20111218063054.GA4979@localhost> <20111218113237.GA1359@localhost> <20120105015609.GA7913@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: "linux-ext4@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , LKML To: Wu Fengguang Return-path: Received: from mail-tul01m020-f174.google.com ([209.85.214.174]:63681 "EHLO mail-tul01m020-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757709Ab2AECXN convert rfc822-to-8bit (ORCPT ); Wed, 4 Jan 2012 21:23:13 -0500 In-Reply-To: <20120105015609.GA7913@localhost> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi Fengguang, > [ =A0646.051405] =A0ffff880004ee1978 0000000000000000 000000000000017= 0 0000000000000000 > [ =A0646.051405] Call Trace: > [ =A0646.051405] =A0[] ? sched_clock_local+0x12/0x7= 5 > [ =A0646.051405] =A0[] lock_acquire+0xdd/0x10a > [ =A0646.051405] =A0[] ? create_empty_buffers+0x4a/= 0xc1 > [ =A0646.051405] =A0[] _raw_spin_lock+0x36/0x69 > [ =A0646.051405] =A0[] ? create_empty_buffers+0x4a/= 0xc1 > [ =A0646.051405] =A0[] create_empty_buffers+0x4a/0x= c1 > [ =A0646.051405] =A0[] ext4_discard_partial_page_bu= ffers_no_lock+0x9f/0x406 > [ =A0646.051405] =A0[] ? _raw_spin_unlock+0x2b/0x2f > [ =A0646.051405] =A0[] ? __mark_inode_dirty+0x1ac/0= x1cc > [ =A0646.051405] =A0[] ? generic_write_end+0x6d/0x7= f > [ =A0646.051405] =A0[] ext4_da_write_end+0x244/0x2e= d > [ =A0646.051405] =A0[] generic_file_buffered_write+= 0x183/0x22d It seems that you are running in to several problems related to discard_page_buffers_no_lock in write_end. The problems had been fixed by following patches [ext4: avoid potential hang in mpage_submit_io() when blocksize < pagesize], [ext4: correctly handle pages w/o buffers in ext4_discard_partial_buffers()] and [ext4: handle EOF correctly in ext4_bio_write_page()]. The patches had been merged to rc6. Yongqiang. > > The test case is about running 100 dd tasks on each of the 10 JBOD di= sks: > > =A0 =A0 =A0 =A0lkp-st02-x8664/JBOD-10HDD-thresh=3D100M/ext4-100dd-1-3= =2E2.0-rc5-ioless-full+ > > Thanks, > Fengguang --=20 Best Wishes Yongqiang Yang -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html