netdev - RE: nfs NULL-dereferencing in net-next

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Date:   Tue, 25 Oct 2016 17:19:33 +0000
From:   Yotam Gigi <yotamg@...lanox.com>
To:     Jakub Kicinski <kubakici@...pl>, Andy Adamson <andros@...app.com>,
        "Anna Schumaker" <Anna.Schumaker@...app.com>,
        "linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Trond Myklebust <Trond.Myklebust@...app.com>,
        Yotam Gigi <yotam.gi@...il.com>, mlxsw <mlxsw@...lanox.com>
Subject: RE: nfs NULL-dereferencing in net-next


>-----Original Message-----
>From: netdev-owner@...r.kernel.org [mailto:netdev-owner@...r.kernel.org] On
>Behalf Of Jakub Kicinski
>Sent: Monday, October 17, 2016 10:20 PM
>To: Andy Adamson <andros@...app.com>; Anna Schumaker
><Anna.Schumaker@...app.com>; linux-nfs@...r.kernel.org
>Cc: netdev@...r.kernel.org; Trond Myklebust <Trond.Myklebust@...app.com>
>Subject: nfs NULL-dereferencing in net-next
>
>Hi!
>
>I'm hitting this reliably on net-next, HEAD at 3f3177bb680f
>("fsl/fman: fix error return code in mac_probe()").


I see the same thing. It happens constantly on some of my machines, making them
completely unusable.

I bisected it and got to the commit:

commit 04ea1b3e6d8ed4978bb608c1748530af3de8c274
Author: Andy Adamson <andros@...app.com>
Date:   Fri Sep 9 09:22:27 2016 -0400

    NFS add xprt switch addrs test to match client
    
    Signed-off-by: Andy Adamson <andros@...app.com>
    Signed-off-by: Anna Schumaker <Anna.Schumaker@...app.com>


>
>[   23.409633] BUG: unable to handle kernel NULL pointer dereference at
>0000000000000172
>[   23.418716] IP: [<ffffffffc041776c>] rpc_clnt_xprt_switch_has_addr+0xc/0x40
>[sunrpc]
>[   23.427574] PGD 859020067 [   23.430472] PUD 858f2d067
>PMD 0 [   23.434311]
>[   23.436133] Oops: 0000 [#1] PREEMPT SMP
>[   23.440506] Modules linked in: nfsv4 ip6table_filter ip6_tables iptable_filter
>ip_tables ebtable_nat ebtables x_tables intel_ri
>[   23.505915] CPU: 1 PID: 1067 Comm: mount.nfs Not tainted 4.8.0-perf-13951-
>g3f3177bb680f #51
>[   23.515363] Hardware name: Dell Inc. PowerEdge T630/0W9WXC, BIOS 1.2.10
>03/10/2015
>[   23.523937] task: ffff983e9086ea00 task.stack: ffffac6c0a57c000
>[   23.530641] RIP: 0010:[<ffffffffc041776c>]  [<ffffffffc041776c>]
>rpc_clnt_xprt_switch_has_addr+0xc/0x40 [sunrpc]
>[   23.542229] RSP: 0018:ffffac6c0a57fb28  EFLAGS: 00010a97
>[   23.548255] RAX: 00000000c80214ac RBX: ffff983e97c7b000 RCX: ffff983e9b3bc180
>[   23.556320] RDX: 0000000000000001 RSI: ffff983e9928ed28 RDI: ffffffffffffffea
>[   23.564386] RBP: ffffac6c0a57fb38 R08: ffff983e97090630 R09: ffff983e9928ed30
>[   23.572452] R10: ffffac6c0a57fba0 R11: 0000000000000010 R12: ffffac6c0a57fba0
>[   23.580517] R13: ffff983e9928ed28 R14: 0000000000000000 R15: ffff983e91360560
>[   23.588585] FS:  00007f4c348aa880(0000) GS:ffff983e9f240000(0000)
>knlGS:0000000000000000
>[   23.597742] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>[   23.604251] CR2: 0000000000000172 CR3: 0000000850a5f000 CR4:
>00000000001406e0
>[   23.612316] Stack:
>[   23.614648]  ffff983e97c7b000 ffffac6c0a57fba0 ffffac6c0a57fb90 ffffffffc04d38c3
>[   23.623331]  ffff983e91360500 ffff983e9928ed30 ffffffffc0b9e560
>ffff983e913605b8
>[   23.632016]  ffff983e9882e800 ffff983e9882e800 ffffac6c0a57fc30 ffffac6c0a57fdb8
>[   23.640706] Call Trace:
>[   23.643535]  [<ffffffffc04d38c3>] nfs_get_client+0x123/0x340 [nfs]
>[   23.650542]  [<ffffffffc0b8f070>] nfs4_set_client+0x80/0xb0 [nfsv4]
>[   23.657642]  [<ffffffffc0b90305>] nfs4_create_server+0x115/0x2a0 [nfsv4]
>[   23.665230]  [<ffffffffc0b888ce>] nfs4_remote_mount+0x2e/0x60 [nfsv4]
>[   23.672519]  [<ffffffffba1e590a>] mount_fs+0x3a/0x160
>[   23.678254]  [<ffffffffba201a5e>] ? alloc_vfsmnt+0x19e/0x230
>[   23.684669]  [<ffffffffba201b57>] vfs_kern_mount+0x67/0x110
>[   23.690990]  [<ffffffffc0b887f4>] nfs_do_root_mount+0x84/0xc0 [nfsv4]
>[   23.698284]  [<ffffffffc0b88b97>] nfs4_try_mount+0x37/0x50 [nfsv4]
>[   23.705287]  [<ffffffffc04dfbd1>] nfs_fs_mount+0x2d1/0xa70 [nfs]
>[   23.712092]  [<ffffffffba3a6228>] ? find_next_bit+0x18/0x20
>[   23.718413]  [<ffffffffc04deac0>] ? nfs_remount+0x3c0/0x3c0 [nfs]
>[   23.725316]  [<ffffffffc04dedb0>] ? nfs_clone_super+0x130/0x130 [nfs]
>[   23.732606]  [<ffffffffba1e590a>] mount_fs+0x3a/0x160
>[   23.738340]  [<ffffffffba201a5e>] ? alloc_vfsmnt+0x19e/0x230
>[   23.744755]  [<ffffffffba201b57>] vfs_kern_mount+0x67/0x110
>[   23.751071]  [<ffffffffba2041df>] do_mount+0x1bf/0xc70
>[   23.756904]  [<ffffffffba203e9b>] ? copy_mount_options+0xbb/0x220
>[   23.763803]  [<ffffffffba204fa3>] SyS_mount+0x83/0xd0
>[   23.769538]  [<ffffffffba6f1ea4>] entry_SYSCALL_64_fastpath+0x17/0x98
>[   23.776817] Code: 01 00 48 8b 93 f8 04 00 00 44 89 e6 48 c7 c7 98 b2 43 c0 e8 9f 0d d4
>f9 eb c0 0f 1f 44 00 00 0f 1f 44 00 00
>[   23.802909] RIP  [<ffffffffc041776c>] rpc_clnt_xprt_switch_has_addr+0xc/0x40
>[sunrpc]
>[   23.811857]  RSP <ffffac6c0a57fb28>
>[   23.815839] CR2: 0000000000000172
>[   23.819629] ---[ end trace 9958eca92c9eeafe ]---
>[   23.827345] note: mount.nfs[1067] exited with preempt_count 1