On Wed, Dec 17, 2008 at 00:08, Ingo Molnar <mingo@xxxxxxx> wrote: >> >> The warning can also be reproduced in qemu, so it was easy to bisect. >> >> commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd >> Author: Nick Piggin <nickpiggin@xxxxxxxxxxxx> >> Date: Tue Sep 30 20:50:27 2008 +1000 >> >> sched: improve preempt debugging >> >> This patch helped me out with a problem I recently had.... >> >> Basically, when the kernel lock is held, then preempt_count >> underflow does not >> get detected until it is released which may be a long time (and arbitrarily, >> eg at different points it may be rescheduled). If the bkl is released at >> schedule, the resulting output is actually fairly cryptic... >> >> With any other lock that elevates preempt_count, it is illegal to schedule >> under it (which would get found pretty quickly). bkl allows scheduling with >> preempt_count elevated, which makes underflows hard to debug. >> >> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> >> >> I understand that not this particular commit is buggy, but at least >> I've got someone to add to the CC. ;) >> >> Also the author's e-mail looks suspicious. > > Suspicious in what way? Does not appear in signed-off-by. > > Ingo > -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
