lkml.org 
[lkml]   [2018]   [Dec]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH AUTOSEL 3.18 06/16] SUNRPC: Fix a potential race in xprt_connect()
    Date
    From: Trond Myklebust <trond.myklebust@hammerspace.com>

    [ Upstream commit 0a9a4304f3614e25d9de9b63502ca633c01c0d70 ]

    If an asynchronous connection attempt completes while another task is
    in xprt_connect(), then the call to rpc_sleep_on() could end up
    racing with the call to xprt_wake_pending_tasks().
    So add a second test of the connection state after we've put the
    task to sleep and set the XPRT_CONNECTING flag, when we know that there
    can be no asynchronous connection attempts still in progress.

    Fixes: 0b9e79431377d ("SUNRPC: Move the test for XPRT_CONNECTING into...")
    Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    net/sunrpc/xprt.c | 11 +++++++++--
    1 file changed, 9 insertions(+), 2 deletions(-)

    diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
    index 56e4e150e80e..dca234b1f77d 100644
    --- a/net/sunrpc/xprt.c
    +++ b/net/sunrpc/xprt.c
    @@ -721,8 +721,15 @@ void xprt_connect(struct rpc_task *task)
    return;
    if (xprt_test_and_set_connecting(xprt))
    return;
    - xprt->stat.connect_start = jiffies;
    - xprt->ops->connect(xprt, task);
    + /* Race breaker */
    + if (!xprt_connected(xprt)) {
    + xprt->stat.connect_start = jiffies;
    + xprt->ops->connect(xprt, task);
    + } else {
    + xprt_clear_connecting(xprt);
    + task->tk_status = 0;
    + rpc_wake_up_queued_task(&xprt->pending, task);
    + }
    }
    }

    --
    2.19.1
    \
     
     \ /
      Last update: 2018-12-13 05:36    [W:2.800 / U:0.400 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site