Messages in this thread | | | Date | Wed, 17 Oct 2007 16:52:26 +0200 | From | Ingo Molnar <> | Subject | Re: [BUG] 2.6.23-git8 kernel oops at __rb_rotate_left+0x7/0x70 |
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* Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> wrote:
> On Wed, Oct 17, 2007 at 04:21:40PM +0200, Ingo Molnar wrote: > > * Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> wrote: > > > > > While running kernbench with the 2.6.23-git8 following oops is > > > produced > > > > Dmitry found something that might explain the crash: could you check > > whether the patch below fixes it? > > > this should fix the put_prev_task crashes that were reported, > > Dmitry Adamushko noticed that it's not valid to call into > > task_new_fair() if this_cpu != task_cpu(p). > > I don't see a fundamental reason why it would be invalid to call > task_new_fair() when this_cpu != task_cpu(p). Besides, calling > activate_task->enqueue_task->enqueue_task_fair() on a new born task > (as is being done in the patch you have sent) is slightly buggy in the > sense that its p->se.vruntime is not properly calculated (because we > set wakeup argument as 0).
yes - i pointed this out in a separate mail.
> We (myself, Kamalesh and Dhaval) have tested the patch below, w/o > being able to recreate the problem. The patch allows for > task_new_fair() to be called even for the case when child is being > added to another cpu's runqueue.
yes, and your fix is the better one, it goes into the next batch of fixes.
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