On Tue, Jan 08, 2013 at 05:16:51PM -0500, Chris Perl wrote: > > The lock is associated with the rpc_task. Threads can normally only > > access an rpc_task when it is on a wait queue (while holding the wait > > queue lock) unless they are given ownership of the rpc_task. > > > > IOW: the scenario you describe should not be possible, since it relies > > on thread 1 assigning the lock to the rpc_task after it has been removed > > from the wait queue. > > Hrm. I guess I'm in over my head here. Apologoies if I'm just asking > silly bumbling questions. You can start ignoring me at any time. :) > > I was talking about setting (or leaving set) the XPRT_LOCKED bit in > rpc_xprt->state. By "assigning the lock" I really just mean that thread > 1 leaves XPRT_LOCKED set in rpc_xprt->state and sets rpc_xprt->snd_task > to thread 2. > > > If you are recompiling the kernel, perhaps you can also add in a patch > > to rpc_show_tasks() to display the current value of > > clnt->cl_xprt->snd_task? > > Sure. This is what 'echo 0 > /proc/sys/sunrpc/rpc_debug' shows after > the hang (with my extra prints): > > # cat /proc/kmsg > ... > <6>client: ffff88082b6c9c00, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 > <6>client: ffff88082b6c9e00, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 > <6>-pid- flgs status -client- --rqstp- -timeout ---ops-- > <6>18091 0080 -11 ffff88082b6c9e00 (null) ffff0770ns3 ACCESS a:call_reserveresult q:xprt_sending > <6>client: ffff88082a244600, xprt: ffff88082a343000, snd_task: (null) > <6>client: ffff880829181600, xprt: ffff88082a343000, snd_task: (null) > <6>client: ffff880828170200, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 Sorry, that output was a little messed up. Here it is again: <6>client: ffff88082b6c9c00, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 <6>client: ffff88082b6c9e00, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 <6>-pid- flgs status -client- --rqstp- -timeout ---ops-- <6>18091 0080 -11 ffff88082b6c9e00 (null) 0 ffffffffa027b7e0 nfsv3 ACCESS a:call_reserveresult q:xprt_sending <6>client: ffff88082a244600, xprt: ffff88082a343000, snd_task: (null) <6>client: ffff880829181600, xprt: ffff88082a343000, snd_task: (null) <6>client: ffff880828170200, xprt: ffff880824aef800, snd_task: ffff881029c63ec0 -- 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
