Return-Path: Received: from mail-qg0-f52.google.com ([209.85.192.52]:35781 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752221AbbCWUT5 (ORCPT ); Mon, 23 Mar 2015 16:19:57 -0400 Received: by qgf74 with SMTP id 74so37487969qgf.2 for ; Mon, 23 Mar 2015 13:19:56 -0700 (PDT) Date: Mon, 23 Mar 2015 16:19:48 -0400 From: Jeff Layton To: Trond Myklebust Cc: linux-nfs@vger.kernel.org Subject: Re: client oops in xdr_reserve_space in 4.0.0-rc4 Message-ID: <20150323161948.7c67feb2@tlielax.poochiereds.net> In-Reply-To: <1427141761.16955.7.camel@primarydata.com> References: <20150322112749.2e2286d3@tlielax.poochiereds.net> <1427141761.16955.7.camel@primarydata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 23 Mar 2015 16:16:01 -0400 Trond Myklebust wrote: > Hi Jeff, > > On Sun, 2015-03-22 at 11:27 -0400, Jeff Layton wrote: > > While trying to track down the use-after-free in nfsd in v4.0-rc > > kernels, I hit this oops on the client. At the time, I had just > > rebooted the server while xfstests generic/011 was running against it. > > It oopsed just after the server came back up. > > > > Kernel is a stock fedora kernel. Looks like xdr_reserve_space failed, > > which triggered a BUG: > > > > [ 9410.321698] run fstests generic/011 at 2015-03-22 11:13:50 > > [ 9737.567073] nfs: server rawhide not responding, still trying > > [ 9839.007187] ------------[ cut here ]------------ > > [ 9839.007923] kernel BUG at fs/nfs/nfs4xdr.c:910! > > [ 9839.008069] invalid opcode: 0000 [#1] SMP > > [ 9839.008069] Modules linked in: blocklayoutdriver rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache snd_hda_codec_generic snd_hda_intel snd_hda_controller snd_hda_codec snd_hwdep snd_seq snd_seq_device snd_pcm joydev iosf_mbi crct10dif_pclmul snd_timer crc32_pclmul crc32c_intel ghash_clmulni_intel snd soundcore ppdev pvpanic parport_pc i2c_piix4 serio_raw virtio_balloon parport acpi_cpufreq nfsd nfs_acl lockd grace auth_rpcgss sunrpc qxl drm_kms_helper virtio_net virtio_console virtio_blk ttm drm virtio_pci virtio_ring virtio ata_generic pata_acpi > > [ 9839.008069] CPU: 0 PID: 308 Comm: kworker/0:1H Not tainted 4.0.0-0.rc4.git1.3.fc23.x86_64 #1 > > [ 9839.008069] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > > [ 9839.008069] Workqueue: rpciod rpc_async_schedule [sunrpc] > > [ 9839.008069] task: ffff8800d8b4d8e0 ti: ffff880036678000 task.ti: ffff880036678000 > > [ 9839.008069] RIP: 0010:[] [] reserve_space.part.73+0x9/0x10 [nfsv4] > > [ 9839.008069] RSP: 0018:ffff88003667ba58 EFLAGS: 00010246 > > [ 9839.008069] RAX: 0000000000000000 RBX: 000000001fc15e18 RCX: ffff8800c0193800 > > [ 9839.008069] RDX: ffff8800e4ae3f24 RSI: 000000001fc15e2c RDI: ffff88003667bcd0 > > [ 9839.008069] RBP: ffff88003667ba58 R08: ffff8800d9173008 R09: 0000000000000003 > > [ 9839.008069] R10: ffff88003667bcd0 R11: 000000000000000c R12: 0000000000010000 > > [ 9839.008069] R13: ffff8800d9173350 R14: 0000000000000000 R15: ffff8800c0067b98 > > [ 9839.008069] FS: 0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000 > > [ 9839.008069] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > [ 9839.008069] CR2: 00007f988c9c8bb0 CR3: 00000000d99b6000 CR4: 00000000000407f0 > > [ 9839.008069] Stack: > > [ 9839.008069] ffff88003667bbc8 ffffffffa03412c5 00000000c6c55680 ffff880000000003 > > [ 9839.008069] 0000000000000088 00000010c6c55680 0001000000000002 ffffffff816e87e9 > > [ 9839.008069] 0000000000000000 00000000477290e2 ffff88003667bab8 ffffffff81327ba3 > > [ 9839.008069] Call Trace: > > [ 9839.008069] [] encode_attrs+0x435/0x530 [nfsv4] > > [ 9839.008069] [] ? inet_sendmsg+0x69/0xb0 > > [ 9839.008069] [] ? selinux_socket_sendmsg+0x23/0x30 > > [ 9839.008069] [] ? do_sock_sendmsg+0x9f/0xc0 > > [ 9839.008069] [] ? kernel_sendmsg+0x58/0x70 > > [ 9839.008069] [] ? xdr_reserve_space+0x20/0x170 [sunrpc] > > [ 9839.008069] [] ? xdr_reserve_space+0x20/0x170 [sunrpc] > > [ 9839.008069] [] ? nfs4_xdr_enc_open_noattr+0x130/0x130 [nfsv4] > > [ 9839.008069] [] encode_open+0x2d5/0x340 [nfsv4] > > [ 9839.008069] [] ? nfs4_xdr_enc_open_noattr+0x130/0x130 [nfsv4] > > [ 9839.008069] [] ? xdr_encode_opaque+0x19/0x20 [sunrpc] > > [ 9839.008069] [] ? encode_string+0x2b/0x40 [nfsv4] > > [ 9839.008069] [] nfs4_xdr_enc_open+0xb3/0x140 [nfsv4] > > [ 9839.008069] [] rpcauth_wrap_req+0xac/0xf0 [sunrpc] > > [ 9839.008069] [] call_transmit+0x18b/0x2d0 [sunrpc] > > [ 9839.008069] [] ? call_decode+0x860/0x860 [sunrpc] > > [ 9839.008069] [] ? call_decode+0x860/0x860 [sunrpc] > > [ 9839.008069] [] __rpc_execute+0x90/0x460 [sunrpc] > > [ 9839.008069] [] rpc_async_schedule+0x15/0x20 [sunrpc] > > [ 9839.008069] [] process_one_work+0x1bb/0x410 > > [ 9839.008069] [] worker_thread+0x53/0x470 > > [ 9839.008069] [] ? process_one_work+0x410/0x410 > > [ 9839.008069] [] ? process_one_work+0x410/0x410 > > [ 9839.008069] [] kthread+0xd8/0xf0 > > [ 9839.008069] [] ? kthread_worker_fn+0x180/0x180 > > [ 9839.008069] [] ret_from_fork+0x58/0x90 > > [ 9839.008069] [] ? kthread_worker_fn+0x180/0x180 > > [ 9839.008069] Code: 00 00 48 c7 c7 21 fa 37 a0 e8 94 1c d6 e0 c6 05 d2 17 05 00 01 8b 03 eb d7 66 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 89 e5 <0f> 0b 0f 1f 44 00 00 66 66 66 66 90 55 48 89 e5 41 54 53 89 f3 > > [ 9839.008069] RIP [] reserve_space.part.73+0x9/0x10 [nfsv4] > > [ 9839.008069] RSP > > [ 9839.071114] ---[ end trace cc14c03adb522e94 ]--- > > > > Could you please check if the following fixes it for you? > > Cheers > Trond Sure, I'll test it when I get some time. Unfortunately, I don't have a way to reproduce this reliably. I just had it pop up a couple of times, mostly when the server crashed and came back up. The fix looks plausible though... -- Jeff > 8<------------------------------------------------------- > From 03e4412b0168c1f4c089ad564c0e3cf91b297596 Mon Sep 17 00:00:00 2001 > From: Trond Myklebust > Date: Mon, 23 Mar 2015 16:10:00 -0400 > Subject: [PATCH] SUNRPC: Fix a regression when reconnecting > > If the task needs to give up the socket lock in order to allow a > reconnect to occur, then it must also clear the 'rq_bytes_sent' field > so that when it retransmits, it knows to start from the beginning. > > Fixes: 718ba5b87343 ("SUNRPC: Add helpers to prevent socket create from racing") > Signed-off-by: Trond Myklebust > --- > net/sunrpc/xprt.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c > index e3015aede0d9..ed4aa786c240 100644 > --- a/net/sunrpc/xprt.c > +++ b/net/sunrpc/xprt.c > @@ -326,6 +326,15 @@ out_unlock: > xprt_clear_locked(xprt); > } > > +static void xprt_task_clear_bytes_sent(struct rpc_task *task) > +{ > + if (task != NULL) { > + struct rpc_rqst *req = task->tk_rqstp; > + if (req != NULL) > + req->rq_bytes_sent = 0; > + } > +} > + > /** > * xprt_release_xprt - allow other requests to use a transport > * @xprt: transport with other tasks potentially waiting > @@ -336,11 +345,7 @@ out_unlock: > void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task) > { > if (xprt->snd_task == task) { > - if (task != NULL) { > - struct rpc_rqst *req = task->tk_rqstp; > - if (req != NULL) > - req->rq_bytes_sent = 0; > - } > + xprt_task_clear_bytes_sent(task); > xprt_clear_locked(xprt); > __xprt_lock_write_next(xprt); > } > @@ -358,11 +363,7 @@ EXPORT_SYMBOL_GPL(xprt_release_xprt); > void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task) > { > if (xprt->snd_task == task) { > - if (task != NULL) { > - struct rpc_rqst *req = task->tk_rqstp; > - if (req != NULL) > - req->rq_bytes_sent = 0; > - } > + xprt_task_clear_bytes_sent(task); > xprt_clear_locked(xprt); > __xprt_lock_write_next_cong(xprt); > } > @@ -700,6 +701,7 @@ bool xprt_lock_connect(struct rpc_xprt *xprt, > goto out; > if (xprt->snd_task != task) > goto out; > + xprt_task_clear_bytes_sent(task); > xprt->snd_task = cookie; > ret = true; > out: -- Jeff Layton