On Fri, Jan 04, 2013 at 01:15:00PM -0500, Trond Myklebust wrote: > 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 <Trond.Myklebust@xxxxxxxxxx> > Cc: Weston Andros Adamson <dros@xxxxxxxxxx> > Cc: Tejun Heo <tj@xxxxxxxxxx> > Cc: Bruce Fields <bfields@xxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx Acked-by: Tejun Heo <tj@xxxxxxxxxx> > + * Tejun Heo states: > + * "Workqueue currently considers two work items to be the same if they're > + * on the same address and won't execute them concurrently - ie. it > + * makes a work item which is queued again while being executed wait > + * for the previous execution to complete. > + * > + * If a work function frees the work item, and then waits for an event > + * which should be performed by another work item and *that* work item > + * recycles the freed work item, it can create a false dependency loop. > + * There really is no reliable way to detect this short of verifying > + * every memory free." I will document it in Documentation/workqueue.txt. Thanks! -- tejun -- 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
