Subject : 2.6.34 hard lock ppp/do_tty_hangup, regression Submitter : Richard Zidlicky <rz@linux-m68k.org> Date : 2010-05-26 8:48 Message-ID : 20100526084811.GA5890@linux-m68k.org References : http://marc.info/?l=linux-kernel&m=127486354023473&w=2 This entry is being used for tracking a regression from 2.6.33. Please don't close it until the problem is fixed in the mainline.
I can not reproduce it anymore no matter how hard I am trying. The only change that I am aware of is this patch which would appear rather unrelated but as it fixes a rather grave spinlock error I can not completely rule out interaction: --- linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c.rz 2010-06-03 21:58:11.000000000 +0200 +++ linux-2.6.34/drivers/media/dvb/siano/smscoreapi.c 2010-06-07 14:32:06.000000000 +0200 @@ -1100,31 +1100,26 @@ * * @return pointer to descriptor on success, NULL on error. */ -struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) + +struct smscore_buffer_t *get_entry(struct smscore_device_t *coredev) { struct smscore_buffer_t *cb = NULL; unsigned long flags; - DEFINE_WAIT(wait); - spin_lock_irqsave(&coredev->bufferslock, flags); - - /* This function must return a valid buffer, since the buffer list is - * finite, we check that there is an available buffer, if not, we wait - * until such buffer become available. - */ - - prepare_to_wait(&coredev->buffer_mng_waitq, &wait, TASK_INTERRUPTIBLE); - - if (list_empty(&coredev->buffers)) - schedule(); - - finish_wait(&coredev->buffer_mng_waitq, &wait); - + if (!list_empty(&coredev->buffers)) { cb = (struct smscore_buffer_t *) coredev->buffers.next; list_del(&cb->entry); - + } spin_unlock_irqrestore(&coredev->bufferslock, flags); + return cb; +} + +struct smscore_buffer_t *smscore_getbuffer(struct smscore_device_t *coredev) +{ + struct smscore_buffer_t *cb = NULL; + + wait_event(coredev->buffer_mng_waitq, (cb = get_entry(coredev))); return cb; }