From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2112C43333 for ; Sat, 21 Mar 2020 14:20:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 775EF20780 for ; Sat, 21 Mar 2020 14:20:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="SmKk9i9r" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727197AbgCUOUg (ORCPT ); Sat, 21 Mar 2020 10:20:36 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:58404 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727192AbgCUOUg (ORCPT ); Sat, 21 Mar 2020 10:20:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+Sr4hdl2JYGj/qj46uquqGH8GuBPuP6vt0K3Ty938fs=; b=SmKk9i9rzrb7u4HwKMgPSyIKMi CQ3N9cI0GgUoP1TAxCpeNryOYhMXnrYKpYLlyd1X0dHDRllOHP42VbfYue7Q8MVn0mzJTT3yOk2I1 9PKe4wpKnYRpRsRfdnvHgPJEInmQkz3iGXr/NzWDKr0tTcQkUeclPSs4Gsk45ODV/8xEbd+BUaxh0 ZJednkPCMvmuDmM5E6/uKaZze1v+8crxrdefpvsIOaulyR0CKpg7/pnUQY7yj4Au8POsrpyrcHW6M LAMJ3zgCz61K1puuI7TemZ7DGuPVa0OnKxnf7pVDXuSCZkGgNtxRIF3Ii0UyvlM7I1zI9RygisWDd F92bxvuA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFezK-0000eV-Kw; Sat, 21 Mar 2020 14:20:34 +0000 Date: Sat, 21 Mar 2020 07:20:34 -0700 From: Matthew Wilcox To: "Darrick J. Wong" Cc: linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, Christoph Hellwig , Jan Kara , Ritesh Harjani , Dave Chinner Subject: Re: [PATCH] iomap: Submit the BIO at the end of each extent Message-ID: <20200321142034.GE4971@bombadil.infradead.org> References: <20200320144014.3276-1-willy@infradead.org> <20200320214654.GC6812@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200320214654.GC6812@magnolia> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Mar 20, 2020 at 02:46:54PM -0700, Darrick J. Wong wrote: > Hmm, I just received the following stack trace while running generic/418 > on a v5 filesystem with 1k blocks: I can't persuade this to reproduce on my setup. > FSTYP -- xfs (debug) > PLATFORM -- Linux/x86_64 alder-mtr01 5.6.0-rc4-djw #rc4 SMP PREEMPT Fri Mar 13 14:48:13 PDT 2020 > MKFS_OPTIONS -- -f -m reflink=1,rmapbt=1 -i sparse=1, -b size=1024, /dev/sdd > MOUNT_OPTIONS -- -o usrquota,grpquota,prjquota, /dev/sdd /opt > > (Note that it seems to do this even with MKFS_OPTIONS='-m crc=0' and > empty MOUNT_OPTIONS.) FSTYP -- xfs (debug) PLATFORM -- Linux/x86_64 bobo-kvm 5.6.0-rc4-00001-g907dfd1bfc6d #2 SMP Fri Mar 20 18:30:53 EDT 2020 MKFS_OPTIONS -- -f -m reflink=1,rmapbt=1 -i sparse=1, -b size=1024 /dev/sdc MOUNT_OPTIONS -- /dev/sdc /mnt/scratch > [ 33.656942] run fstests generic/418 at 2020-03-20 14:42:29 > [ 36.332268] BUG: kernel NULL pointer dereference, address: 0000000000000060 > [ 36.334254] #PF: supervisor read access in kernel mode > [ 36.334849] #PF: error_code(0x0000) - not-present page > [ 36.335461] PGD 0 P4D 0 > [ 36.335779] Oops: 0000 [#1] PREEMPT SMP > [ 36.336246] CPU: 2 PID: 5144 Comm: dio-invalidate- Not tainted 5.6.0-rc4-djw #rc4 > [ 36.337078] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1 04/01/2014 > [ 36.338069] RIP: 0010:iomap_readpage_actor+0x2ea/0x3c0 > [ 36.338671] Code: 43 10 8b 54 24 24 48 c7 40 38 80 bc 2f 81 48 8b 7b 10 e9 00 ff ff ff 31 c0 48 85 ed 0f 85 c9 fe ff ff 49 8b 46 18 48 8b 2c 24 <8b> 48 60 48 81 c5 ff 0f 00 00 48 c1 ed 0c 81 e1 c0 0c 00 00 e9 12 > [ 36.340705] RSP: 0018:ffffc90004ebb968 EFLAGS: 00010246 > [ 36.341309] RAX: 0000000000000000 RBX: ffffc90004ebbb30 RCX: 000000000000000a > [ 36.342105] RDX: 0000000000000400 RSI: 0000000000000003 RDI: 0000000000000000 > [ 36.342909] RBP: 0000000000000400 R08: ffffc90004ebb988 R09: ffffc90004ebb98c > [ 36.343710] R10: 0000000000001000 R11: 0000000000000400 R12: ffffc90004ebba50 > [ 36.344505] R13: 0000000000000086 R14: ffffea0001cd2400 R15: 0000000000000c00 > [ 36.345246] FS: 00007f892894c740(0000) GS:ffff88807e000000(0000) knlGS:0000000000000000 > [ 36.346087] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 36.346696] CR2: 0000000000000060 CR3: 0000000078753005 CR4: 00000000001606a0 > [ 36.347445] Call Trace: > [ 36.347734] iomap_readpages_actor+0x1e3/0x250 > [ 36.348699] iomap_apply+0x12c/0x4e3 > [ 36.349097] ? iomap_readpage_actor+0x3c0/0x3c0 > [ 36.349593] ? prep_new_page+0x3f/0x100 > [ 36.350022] ? iomap_readpage_actor+0x3c0/0x3c0 > [ 36.350519] iomap_readpages+0xc7/0x2b0 > [ 36.350938] ? iomap_readpage_actor+0x3c0/0x3c0 > [ 36.351438] read_pages+0x6e/0x1a0 > [ 36.351824] __do_page_cache_readahead+0x1c3/0x1e0 > [ 36.352343] ondemand_readahead+0x210/0x4b0 > [ 36.352797] generic_file_read_iter+0x871/0xcd0 > [ 36.353365] ? xfs_file_buffered_aio_read+0x54/0x170 [xfs] > [ 36.353982] xfs_file_buffered_aio_read+0x5f/0x170 [xfs] > [ 36.354591] xfs_file_read_iter+0xea/0x2a0 [xfs] > [ 36.355139] ? xfs_file_write_iter+0xf2/0x1d0 [xfs] > [ 36.355668] new_sync_read+0x12d/0x1d0 > [ 36.356085] vfs_read+0xa6/0x180 > [ 36.356454] ksys_pread64+0x64/0xa0 > [ 36.356841] do_syscall_64+0x50/0x1a0 > [ 36.357252] entry_SYSCALL_64_after_hwframe+0x49/0xbe > [ 36.357792] RIP: 0033:0x7f8928524f64 > [ 36.358189] Code: 15 61 80 20 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 8b 05 aa c4 20 00 49 89 ca 85 c0 75 13 b8 11 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5c f3 c3 66 90 41 55 41 54 49 89 cd 55 53 49 > [ 36.360053] RSP: 002b:00007fffc7893b18 EFLAGS: 00000246 ORIG_RAX: 0000000000000011 > [ 36.360841] RAX: ffffffffffffffda RBX: 0000000000000400 RCX: 00007f8928524f64 > [ 36.361594] RDX: 0000000000000400 RSI: 00005593e3c23000 RDI: 0000000000000003 > [ 36.362344] RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000001 > [ 36.363075] R10: 0000000000000000 R11: 0000000000000246 R12: 00005593e3c23000 > [ 36.363817] R13: 0000000000000000 R14: 00005593e3c25000 R15: 0000000000000400 > [ 36.364569] Modules linked in: xfs libcrc32c ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 ip_set_hash_ip ip_set_hash_net xt_tcpudp xt_set ip_set_hash_mac ip_set nfnetlink ip6table_filter ip6_tables iptable_filter bfq sch_fq_codel ip_tables x_tables nfsv4 af_packet > [ 36.366966] Dumping ftrace buffer: > [ 36.367351] (ftrace buffer empty) > [ 36.367742] CR2: 0000000000000060 > [ 36.369050] ---[ end trace d599586d1259866c ]--- > [ 36.369884] RIP: 0010:iomap_readpage_actor+0x2ea/0x3c0 > [ 36.370694] Code: 43 10 8b 54 24 24 48 c7 40 38 80 bc 2f 81 48 8b 7b 10 e9 00 ff ff ff 31 c0 48 85 ed 0f 85 c9 fe ff ff 49 8b 46 18 48 8b 2c 24 <8b> 48 60 48 81 c5 ff 0f 00 00 48 c1 ed 0c 81 e1 c0 0c 00 00 e9 12 > [ 36.373022] RSP: 0018:ffffc90004ebb968 EFLAGS: 00010246 > [ 36.373615] RAX: 0000000000000000 RBX: ffffc90004ebbb30 RCX: 000000000000000a > [ 36.374362] RDX: 0000000000000400 RSI: 0000000000000003 RDI: 0000000000000000 > [ 36.375100] RBP: 0000000000000400 R08: ffffc90004ebb988 R09: ffffc90004ebb98c > [ 36.375833] R10: 0000000000001000 R11: 0000000000000400 R12: ffffc90004ebba50 > [ 36.376577] R13: 0000000000000086 R14: ffffea0001cd2400 R15: 0000000000000c00 > [ 36.377322] FS: 00007f892894c740(0000) GS:ffff88807e000000(0000) knlGS:0000000000000000 > [ 36.378190] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 36.378795] CR2: 0000000000000060 CR3: 0000000078753005 CR4: 00000000001606a0 This doesn't entirely match your backtrace, but this looks wrong: if (ctx->is_readahead) /* same as readahead_gfp_mask */ gfp |= __GFP_NORETRY | __GFP_NOWARN; ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs)); ctx->bio->bi_opf = REQ_OP_READ; If we're specifying NORETRY, then we have to handle bio_alloc() failure here, right? I say it doesn't entirely match because you've got a read from an offset of 0x60, and every access here is a write.