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| author | Bill.Baker@oracle.com <Bill.Baker@oracle.com> | 2018-02-21 12:46:43 -0600 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2018-02-22 12:17:42 -0500 |
| commit | ad86f605c59500da82d196ac312cfbac3daba31d (patch) | |
| tree | cfe82b4a4f44c4e4371af646307390f122389f23 /fs/nfs/nfs4client.c | |
| parent | 6d243a235612946971ba98f24f52dc99f4ebb32a (diff) | |
| download | linux-ad86f605c59500da82d196ac312cfbac3daba31d.tar.gz linux-ad86f605c59500da82d196ac312cfbac3daba31d.tar.bz2 linux-ad86f605c59500da82d196ac312cfbac3daba31d.zip | |
nfs: system crashes after NFS4ERR_MOVED recovery
nfs4_update_server unconditionally releases the nfs_client for the
source server. If migration fails, this can cause the source server's
nfs_client struct to be left with a low reference count, resulting in
use-after-free. Also, adjust reference count handling for ELOOP.
NFS: state manager: migration failed on NFSv4 server nfsvmu10 with error 6
WARNING: CPU: 16 PID: 17960 at fs/nfs/client.c:281 nfs_put_client+0xfa/0x110 [nfs]()
nfs_put_client+0xfa/0x110 [nfs]
nfs4_run_state_manager+0x30/0x40 [nfsv4]
kthread+0xd8/0xf0
BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8
nfs4_xdr_enc_write+0x6b/0x160 [nfsv4]
rpcauth_wrap_req+0xac/0xf0 [sunrpc]
call_transmit+0x18c/0x2c0 [sunrpc]
__rpc_execute+0xa6/0x490 [sunrpc]
rpc_async_schedule+0x15/0x20 [sunrpc]
process_one_work+0x160/0x470
worker_thread+0x112/0x540
? rescuer_thread+0x3f0/0x3f0
kthread+0xd8/0xf0
This bug was introduced by 32e62b7c ("NFS: Add nfs4_update_server"),
but the fix applies cleanly to 52442f9b ("NFS4: Avoid migration loops")
Reported-by: Helen Chao <helen.chao@oracle.com>
Fixes: 52442f9b11b7 ("NFS4: Avoid migration loops")
Signed-off-by: Bill Baker <bill.baker@oracle.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/nfs4client.c')
| -rw-r--r-- | fs/nfs/nfs4client.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c index 04612c24d394..979631411a0e 100644 --- a/fs/nfs/nfs4client.c +++ b/fs/nfs/nfs4client.c @@ -868,8 +868,10 @@ static int nfs4_set_client(struct nfs_server *server, if (IS_ERR(clp)) return PTR_ERR(clp); - if (server->nfs_client == clp) + if (server->nfs_client == clp) { + nfs_put_client(clp); return -ELOOP; + } /* * Query for the lease time on clientid setup or renewal @@ -1244,11 +1246,11 @@ int nfs4_update_server(struct nfs_server *server, const char *hostname, clp->cl_proto, clnt->cl_timeout, clp->cl_minorversion, net); clear_bit(NFS_MIG_TSM_POSSIBLE, &server->mig_status); - nfs_put_client(clp); if (error != 0) { nfs_server_insert_lists(server); return error; } + nfs_put_client(clp); if (server->nfs_client->cl_hostname == NULL) server->nfs_client->cl_hostname = kstrdup(hostname, GFP_KERNEL); |