On Mon, 2014-03-03 at 10:33 +0800, Yan, Zheng wrote: > Hi, > > I got following Oops when running fsstress > --- > [ 2536.142216] BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 > [ 2536.143110] IP: [<ffffffff813391d9>] memcmp+0x9/0x50 > [ 2536.143110] PGD 0 > [ 2536.143110] Oops: 0000 [#1] SMP > [ 2536.143110] Modules linked in: rpcsec_gss_krb5(F) auth_rpcgss(F) nfsv4(F) dns_resolver(F) nfs(F) fscache(F) ceph(F) libceph(F) libcrc32c(F) netconsole(F) ip6table_filter(F) ip6_tables(F) ebtable_nat(F) ebtables(F) ipt_MASQUERADE(F) iptable_nat(F) nf_nat_ipv4(F) nf_nat(F) nf_conntrack_ipv4(F) nf_defrag_ipv4(F) xt_state(F) nf_conntrack(F) xt_CHECKSUM(F) iptable_mangle(F) bnep(F) bluetooth(F) 6lowpan_iphc(F) bridge(F) lockd(F) sunrpc(F) rfkill(F) be2iscsi(F) iscsi_boot_sysfs(F) stp(F) llc(F) bnx2i(F) cnic(F) uio(F) cxgb4i(F) cxgb4(F) cxgb3i(F) cxgb3(F) mdio(F) libcxgbi(F) ib_iser(F) rdma_cm(F) iw_cm(F) ib_cm(F) ib_sa(F) ib_mad(F) ib_core(F) ib_addr(F) iscsi_tcp(F) libiscsi_tcp(F) libiscsi(F) scsi_transport_iscsi(F) virtio_net(F) virtio_balloon(F) pcspkr(F) microcode(F) uinput(F) cirrus(F) drm_kms_helper(F) ttm(F) drm(F) i2c_core(F) > [ 2536.143110] CPU: 1 PID: 2925 Comm: nfsv4.0-svc Tainted: GF 3.14.0-rc4+ #50 > [ 2536.143110] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 > [ 2536.143110] task: ffff88003cd55aa0 ti: ffff88003c9a8000 task.ti: ffff88003c9a8000 > [ 2536.143110] RIP: 0010:[<ffffffff813391d9>] [<ffffffff813391d9>] memcmp+0x9/0x50 > [ 2536.143110] RSP: 0018:ffff88003c9a9ca8 EFLAGS: 00010202 > [ 2536.143110] RAX: ffffffffa04842c0 RBX: 0000000000000000 RCX: 0000000000000036 > [ 2536.143110] RDX: 0000000000000010 RSI: ffff880035ee808a RDI: 0000000000000020 > [ 2536.143110] RBP: ffff88003c9a9ca8 R08: 8020000000000000 R09: 00231b6840100000 > [ 2536.143110] R10: ffbee4a086ca1004 R11: 0000000000000000 R12: ffff88003751e000 > [ 2536.143110] R13: ffff880034afa000 R14: ffff880035ee808a R15: 0000000000000004 > [ 2536.143110] FS: 0000000000000000(0000) GS:ffff88003fc80000(0000) knlGS:0000000000000000 > [ 2536.143110] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b > [ 2536.143110] CR2: 0000000000000020 CR3: 0000000034bc0000 CR4: 00000000000006e0 > [ 2536.143110] Stack: > [ 2536.143110] ffff88003c9a9cb8 ffffffffa0455883 ffff88003c9a9cf0 ffffffffa0472b98 > [ 2536.143110] ffff880035ee8000 ffff880035ee8000 ffff8800231b6970 0000000011270000 > [ 2536.143110] 0000000000000000 ffff88003c9a9d28 ffffffffa0475fc9 ffff88003c9a9d28 > [ 2536.143110] Call Trace: > [ 2536.143110] [<ffffffffa0455883>] nfs4_match_stateid+0x13/0x20 [nfsv4] > [ 2536.143110] [<ffffffffa0472b98>] nfs_async_inode_return_delegation+0x48/0x90 [nfsv4] > [ 2536.143110] [<ffffffffa0475fc9>] nfs4_callback_recall+0x59/0x130 [nfsv4] > [ 2536.143110] [<ffffffffa0475005>] nfs4_callback_compound+0x465/0x6a0 [nfsv4] > [ 2536.143110] [<ffffffffa0220c1a>] ? svcauth_unix_accept+0x14a/0x270 [sunrpc] > [ 2536.143110] [<ffffffffa021c707>] svc_process_common+0x5e7/0x6e0 [sunrpc] > [ 2536.143110] [<ffffffffa0473e80>] ? nfs_callback_authenticate+0x50/0x50 [nfsv4] > [ 2536.143110] [<ffffffffa021c907>] svc_process+0x107/0x170 [sunrpc] > [ 2536.143110] [<ffffffffa0473e80>] ? nfs_callback_authenticate+0x50/0x50 [nfsv4] > [ 2536.143110] [<ffffffffa0473ec5>] nfs4_callback_svc+0x45/0x60 [nfsv4] > [ 2536.143110] [<ffffffff810a4a52>] kthread+0xd2/0xf0 > [ 2536.143110] [<ffffffff810a4980>] ? insert_kthread_work+0x40/0x40 > [ 2536.143110] [<ffffffff816b567c>] ret_from_fork+0x7c/0xb0 > [ 2536.143110] [<ffffffff810a4980>] ? insert_kthread_work+0x40/0x40 > [ 2536.143110] Code: 75 e9 31 c0 c6 06 01 5d c3 66 0f 1f 84 00 00 00 00 00 31 c0 c6 06 00 5d c3 66 0f 1f 84 00 00 00 00 00 55 48 85 d2 48 89 e5 74 3c <0f> b6 07 0f b6 0e 29 c8 75 27 48 83 ea 01 31 c9 eb 1a 0f 1f 44 > [ 2536.143110] RIP [<ffffffff813391d9>] memcmp+0x9/0x50 > [ 2536.143110] RSP <ffff88003c9a9ca8> > [ 2536.143110] CR2: 0000000000000020 > [ 2536.143110] ---[ end trace 145a1eb5268045c7 ]--- Does the following patch help? Cheers Trond 8<--------------------------------------------------------------- >From 755a48a7a4eb05b9c8424e3017d947b2961a60e0 Mon Sep 17 00:00:00 2001 From: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> Date: Sun, 2 Mar 2014 22:03:12 -0500 Subject: [PATCH] NFS: Fix a delegation callback race The clean-up in commit 36281caa839f ended up removing a NULL pointer check that is needed in order to prevent an Oops in nfs_async_inode_return_delegation(). Reported-by: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx> Link: http://lkml.kernel.org/r/5313E9F6.2020405@xxxxxxxxx Fixes: 36281caa839f (NFSv4: Further clean-ups of delegation stateid validation) Cc: stable@xxxxxxxxxxxxxxx # 3.4+ Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> --- fs/nfs/delegation.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index ef792f29f831..5d8ccecf5f5c 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -659,16 +659,19 @@ int nfs_async_inode_return_delegation(struct inode *inode, rcu_read_lock(); delegation = rcu_dereference(NFS_I(inode)->delegation); + if (delegation == NULL) + goto out_enoent; - if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) { - rcu_read_unlock(); - return -ENOENT; - } + if (!clp->cl_mvops->match_stateid(&delegation->stateid, stateid)) + goto out_enoent; nfs_mark_return_delegation(server, delegation); rcu_read_unlock(); nfs_delegation_run_state_manager(clp); return 0; +out_enoent: + rcu_read_unlock(); + return -ENOENT; } static struct inode * -- 1.8.5.3 -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@xxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
