linux-stable.git/net/sunrpc, branch v3.7.7

SUNRPC: Ensure we release the socket write lock if the rpc_task exits early

2013-01-17T16:46:08+00:00

commit 87ed50036b866db2ec2ba16b2a7aec4a2b0b7c39 upstream.

If the rpc_task exits while holding the socket write lock before it has
allocated an rpc slot, then the usual mechanism for releasing the write
lock in xprt_release() is defeated.

The problem occurs if the call to xprt_lock_write() initially fails, so
that the rpc_task is put on the xprt->sending wait queue. If the task
exits after being assigned the lock by __xprt_lock_write_func, but
before it has retried the call to xprt_lock_and_alloc_slot(), then
it calls xprt_release() while holding the write lock, but will
immediately exit due to the test for task->tk_rqstp != NULL.

Reported-by: Chris Perl 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Ensure that we free the rpc_task after cleanups are done

2013-01-17T16:46:08+00:00

commit c6567ed1402c55e19b012e66a8398baec2a726f3 upstream.

This patch ensures that we free the rpc_task after the cleanup callbacks
are done in order to avoid a deadlock problem that can be triggered if
the callback needs to wait for another workqueue item to complete.

Signed-off-by: Trond Myklebust 
Cc: Weston Andros Adamson 
Cc: Tejun Heo 
Cc: Bruce Fields 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: continue run over clients list on PipeFS event instead of break

2013-01-17T16:46:08+00:00

commit cd6c5968582a273561464fe6b1e8cc8214be02df upstream.

There are SUNRPC clients, which program doesn't have pipe_dir_name. These
clients can be skipped on PipeFS events, because nothing have to be created or
destroyed. But instead of breaking in case of such a client was found, search
for suitable client over clients list have to be continued. Otherwise some
clients could not be covered by PipeFS event handler.

Signed-off-by: Stanislav Kinsbursky 
Signed-off-by: Trond Myklebust 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: Fix validity issues with rpc_pipefs sb->s_fs_info

2013-01-17T16:46:08+00:00

commit 642fe4d00db56d65060ce2fd4c105884414acb16 upstream.

rpc_kill_sb() must defer calling put_net() until after the notifier
has been called, since most (all?) of the notifier callbacks assume
that sb->s_fs_info points to a valid net namespace. It also must not
call put_net() if the call to rpc_fill_super was unsuccessful.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=48421

Signed-off-by: Trond Myklebust 
Cc: Stanislav Kinsbursky 
Signed-off-by: Greg Kroah-Hartman

SUNRPC: return proper errno from backchannel_rqst

2012-11-01T15:50:53+00:00

The one and only caller (in fs/nfs/nfs4client.c) uses the result
as an errno and would have interpreted an error as EPERM.

Signed-off-by: Weston Andros Adamson 
Signed-off-by: Trond Myklebust

SUNRPC: Get rid of the xs_error_report socket callback

2012-10-24T14:46:15+00:00

Chris Perl reports that we're seeing races between the wakeup call in
xs_error_report and the connect attempts. Basically, Chris has shown
that in certain circumstances, the call to xs_error_report causes the
rpc_task that is responsible for reconnecting to wake up early, thus
triggering a disconnect and retry.

Since the sk->sk_error_report() calls in the socket layer are always
followed by a tcp_done() in the cases where we care about waking up
the rpc_tasks, just let the state_change callbacks take responsibility
for those wake ups.

Reported-by: Chris Perl 
Signed-off-by: Trond Myklebust 
Cc: stable@vger.kernel.org
Tested-by: Chris Perl

SUNRPC: Prevent races in xs_abort_connection()

2012-10-24T14:46:08+00:00

The call to xprt_disconnect_done() that is triggered by a successful
connection reset will trigger another automatic wakeup of all tasks
on the xprt->pending rpc_wait_queue. In particular it will cause an
early wake up of the task that called xprt_connect().

All we really want to do here is clear all the socket-specific state
flags, so we split that functionality out of xs_sock_mark_closed()
into a helper that can be called by xs_abort_connection()

Reported-by: Chris Perl 
Signed-off-by: Trond Myklebust 
Cc: stable@vger.kernel.org
Tested-by: Chris Perl

Revert "SUNRPC: Ensure we close the socket on EPIPE errors too..."

2012-10-24T14:45:39+00:00

This reverts commit 55420c24a0d4d1fce70ca713f84aa00b6b74a70e.
Now that we clear the connected flag when entering TCP_CLOSE_WAIT,
the deadlock described in this commit is no longer possible.
Instead, the resulting call to xs_tcp_shutdown() can interfere
with pending reconnection attempts.

Reported-by: Chris Perl 
Signed-off-by: Trond Myklebust 
Cc: stable@vger.kernel.org
Tested-by: Chris Perl

SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT

2012-10-24T14:44:49+00:00

This is needed to ensure that we call xprt_connect() upon the next
call to call_connect().

Signed-off-by: Trond Myklebust 
Cc: stable@vger.kernel.org
Tested-by: Chris Perl

SUNRPC: Prevent kernel stack corruption on long values of flush

2012-10-17T18:59:10+00:00

The buffer size in read_flush() is too small for the longest possible values
for it. This can lead to a kernel stack corruption:

[   43.047329] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: ffffffff833e64b4
[   43.047329]
[   43.049030] Pid: 6015, comm: trinity-child18 Tainted: G        W    3.5.0-rc7-next-20120716-sasha #221
[   43.050038] Call Trace:
[   43.050435]  [] panic+0xcd/0x1f4
[   43.050931]  [] ? read_flush.isra.7+0xe4/0x100
[   43.051602]  [] __stack_chk_fail+0x16/0x20
[   43.052206]  [] read_flush.isra.7+0xe4/0x100
[   43.052951]  [] ? read_flush_pipefs+0x30/0x30
[   43.053594]  [] read_flush_procfs+0x2c/0x30
[   43.053596]  [] proc_reg_read+0x9c/0xd0
[   43.053596]  [] ? proc_reg_write+0xd0/0xd0
[   43.053596]  [] do_loop_readv_writev+0x4b/0x90
[   43.053596]  [] do_readv_writev+0xf6/0x1d0
[   43.053596]  [] vfs_readv+0x3e/0x60
[   43.053596]  [] sys_readv+0x48/0xb0
[   43.053596]  [] system_call_fastpath+0x1a/0x1f

Signed-off-by: Sasha Levin 
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields