Revert "sched: improve preempt debugging"

This reverts commit 7317d7b87edb41a9135e30be1ec3f7ef817c53dd.

This has been reported (and bisected) by Alexey Zaytsev and
Kamalesh Babulal to produce annoying warnings during bootup
on both x86 and powerpc.

kernel_locked() is not a valid test in IRQ context (we update the
BKL's ->lock_depth and the preempt count separately and non-atomicalyy),
so we cannot put it into the generic preempt debugging checks which
can run in IRQ contexts too.

Reported-and-bisected-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Reported-and-bisected-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/sched.c b/kernel/sched.c
index 8be2c13b50d018cc69280829e14e31612d4deddd..3b630d8826605eb4e579a2b2ae48208b52f2de22 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4440,7 +4440,7 @@ void __kprobes sub_preempt_count(int val)
        /*
         * Underflow?
         */
-       if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked())))
+       if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
                return;
        /*
         * Is the spinlock portion underflowing?