NFS: Ensure that rpc_release_resources_task() can be called twice.
BUG: atomic_dec_and_test(): -1: atomic counter underflow at:
Pid: 2827, comm: mount.nfs Not tainted 2.6.38 #1
Call Trace:
[<ffffffffa02223a0>] ? put_rpccred+0x44/0x14e [sunrpc]
[<ffffffffa021bbe9>] ? rpc_ping+0x4e/0x58 [sunrpc]
[<ffffffffa021c4a5>] ? rpc_create+0x481/0x4fc [sunrpc]
[<ffffffffa022298a>] ? rpcauth_lookup_credcache+0xab/0x22d [sunrpc]
[<ffffffffa028be8c>] ? nfs_create_rpc_client+0xa6/0xeb [nfs]
[<ffffffffa028c660>] ? nfs4_set_client+0xc2/0x1f9 [nfs]
[<ffffffffa028cd3c>] ? nfs4_create_server+0xf2/0x2a6 [nfs]
[<ffffffffa0295d07>] ? nfs4_remote_mount+0x4e/0x14a [nfs]
[<ffffffff810dd570>] ? vfs_kern_mount+0x6e/0x133
[<ffffffffa029605a>] ? nfs_do_root_mount+0x76/0x95 [nfs]
[<ffffffffa029643d>] ? nfs4_try_mount+0x56/0xaf [nfs]
[<ffffffffa0297434>] ? nfs_get_sb+0x435/0x73c [nfs]
[<ffffffff810dd59b>] ? vfs_kern_mount+0x99/0x133
[<ffffffff810dd693>] ? do_kern_mount+0x48/0xd8
[<ffffffff810f5b75>] ? do_mount+0x6da/0x741
[<ffffffff810f5c5f>] ? sys_mount+0x83/0xc0
[<ffffffff8100293b>] ? system_call_fastpath+0x16/0x1b
Well, so, I think this is real bug of nfs codes somewhere. With some
review, the code
rpc_call_sync()
rpc_run_task
rpc_execute()
__rpc_execute()
rpc_release_task()
rpc_release_resources_task()
put_rpccred() <= release cred
rpc_put_task
rpc_do_put_task()
rpc_release_resources_task()
put_rpccred() <= release cred again
seems to be release cred unintendedly.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
a271c5a0de