On Sat, 2013-02-16 at 00:34 +0800, buyitian wrote: > I am looking at version 3.4 > > 在 2013-2-16，0:17，Valdis.Kletnieks@xxxxxx 写道： > > > On Fri, 15 Feb 2013 17:17:38 +0530, anish singh said: > >> adding Joe Perches as generally he looks after printk stuff. > >> > >> On Fri, Feb 15, 2013 at 2:22 PM, buyitian <buyit@xxxxxxx> wrote: > >>> is it possible that printk cause deadlock? the path is as below: > >>> > >>> 1. taskA runs on CPU0, and run schedule to acqire the rq->lock. > >>> 2. taskA calls printk while holding rq->lock. > >>> 3. taskA holds console_sem. > >>> 4. taskB runs on CPU1, and call console_lock(), which is blocked by > >>> console_sem and queue itslef to the wait list. > >>> 5. taskB migrates from CPU1 to cpu0. will this step occur? > >>> 6. taskA calls up(&console_sem)--> > >>> wake_up_process()-->try_to_wake_up()-->ttwu_queue()-->raw_spin_lock(&rq->lock). > >>> here taskA tries to acquire the rq->lock of CPU0 again. > > > > I'm not Joe, but what kernel release are you looking at? ISTR that in > > the last few releases (3.5-ish maybe?), that code got overhauled to > > prevent a similar issue.. Can you ask this question in kernel maling list?I think you might get a better reply to your queries. > > _______________________________________________ > > Kernelnewbies mailing list > > Kernelnewbies@xxxxxxxxxxxxxxxxx > > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
