On Thu, Oct 02, 2014 at 08:38:46AM -0400, Peter Hurley wrote: > On 10/02/2014 08:31 AM, Peter Zijlstra wrote: > > On Thu, Oct 02, 2014 at 01:09:27PM +0200, Peter Zijlstra wrote: > >> On Tue, Sep 30, 2014 at 04:02:28PM +0800, Fengguang Wu wrote: > >>> Hi Peter, > >>> > >>> We possibly find a rfcomm bug (maintainers CCed) exposed by your debug > >>> patch > >>> > >>> [ 1.861895] NET: Registered protocol family 5 > >>> [ 1.862978] Bluetooth: RFCOMM TTY layer initialized > >>> [ 1.863099] ------------[ cut here ]------------ > >>> [ 1.863105] WARNING: CPU: 1 PID: 79 at kernel/sched/core.c:7156 > >>> __might_sleep+0x17d/0x1a1() > >>> [ 1.863112] do not call blocking ops when !TASK_RUNNING; state=1 set > >>> at [<c14dc381>] rfcomm_run+0xdf/0x130e > >>> [ 1.863591] [<c1058b73>] ? kthread_stop+0x53/0x53 > >>> [ 1.864906] [<c155a411>] dump_stack+0x48/0x60 > >>> [ 1.866298] [<c14dc381>] ? rfcomm_run+0xdf/0x130e > >> > >> Ha yes, rfcomm_run is a complete buggy mess indeed. Lemme go see what I > >> can make of it. > > > > --- > > Subject: rfcomm: Fix broken wait construct > > > > rfcomm_run() is a tad broken in that is has a nested wait loop. One > > cannot rely on p->state for the outer wait because the inner wait will > > overwrite it. > > > > While at it, rename rfcomm_schedule to rfcomm_wake, since that is what > > it actually does. > > rfcomm_schedule() as in schedule_work(), which is how it's used.
Not really, all it does is wake the rfcomm_thread. The thread then does a linear walk of all known sessions looking for work -- which is clearly suboptimal as well, but I didn't feel like fixing that. Also, the current implementation already disagrees with you, all it basically does it call wake_up_process() which is a big clue right there. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
