From 3a5f5e488ceee9e08df3dff3f01b12fafc9e7e68 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 14 Jul 2006 00:24:27 -0700 Subject: [PATCH] [PATCH] lockdep: core, fix rq-lock handling on __ARCH_WANT_UNLOCKED_CTXSW On platforms that have __ARCH_WANT_UNLOCKED_CTXSW set and want to implement lock validator support there's a bug in rq->lock handling: in this case we dont 'carry over' the runqueue lock into another task - but still we did a spinlock_release() of it. Fix this by making the spinlock_release() in context_switch() dependent on !__ARCH_WANT_UNLOCKED_CTXSW. (Reported by Ralf Baechle on MIPS, which has __ARCH_WANT_UNLOCKED_CTXSW. This fixes a lockdep-internal BUG message on such platforms.) Signed-off-by: Ingo Molnar Cc: Ralf Baechle Cc: Arjan van de Ven Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/sched.c b/kernel/sched.c index d714611f1691..e9a0b61f12ab 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1788,7 +1788,15 @@ context_switch(struct rq *rq, struct task_struct *prev, WARN_ON(rq->prev_mm); rq->prev_mm = oldmm; } + /* + * Since the runqueue lock will be released by the next + * task (which is an invalid locking op but in the case + * of the scheduler it's an obvious special-case), so we + * do an early lockdep release here: + */ +#ifndef __ARCH_WANT_UNLOCKED_CTXSW spin_release(&rq->lock.dep_map, 1, _THIS_IP_); +#endif /* Here we just switch the register state and the stack. */ switch_to(prev, next, prev);