On Tue, Jan 16, 2018 at 02:19:20PM +0100, Martin Wilck wrote: > On Tue, 2018-01-16 at 11:48 +0000, Wuchongyun wrote: > > Hi Martin, > > Sorry to forget that, actually I found that dead_client() will not be > > interrupt by thread cancle, because after all dead_client() calling > > point be done then handle_signals() have chance to be called by > > uxsock_listen() which will call exit_daemon() and send > > cancel threads signal to all child process include uxlsnr. > > Fair enough. > > > But your comments is good can make code more safer. Below is the new > > patch, please have a look, thanks. > > I think it's really safer whis way, should anyone see the need to > cancel the listener thread from another point in the code. I'm confused why this is safe. After uxsock_listen() calls exit_daemon() from handle_signals(), it doesn't exit. It loops around and polls again, and could in theory find a client that has died. In fact if the client is killing multipathd via # multipathd shutdown instead of a signal, won't it be very likely that it will find a dead client when it loops right after calling exit_daemon() in cli_shutdown()? This could hit the deadlock that you noticed, where uxsock_cleanup() can't run because dead_client() already holding the mutex. Or am I missing something here? -Ben > > The patch is looks good now. > > Reviewed-by: Martin Wilck <mwilck@xxxxxxxx> > > -- > Dr. Martin Wilck <mwilck@xxxxxxxx>, Tel. +49 (0)911 74053 2107 > SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton > HRB 21284 (AG Nürnberg) > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
