softirq/preempt: add missing current->preempt_disable_ip update

While debugging some "sleeping function called from invalid context" bug I realized that the debug message "Preemption disabled at:" pointed to an incorrect function.
In particular if the function/action that disabled preemption was spin_lock_bh() then current->preempt_disable_ip won't be updated.

The reason for this is that __local_bh_disable_ip() will increase preempt_count manually instead of calling preempt_count_add(), which would handle the update correctly.
It look like the manual handling was done to work around some lockdep issue.

So add the missing update of current->preempt_disable_ip to __local_bh_disable_ip() as well.

Signed-off-by Heiko Carstens <[email protected]>

---
 kernel/softirq.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

kernel/softirq.c +0 -2

index 501baa9ac1be..edd51027e3ab 100644
@@ -114,8 +114,13 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
 		trace_softirqs_off(ip);
 	raw_local_irq_restore(flags);
 
-	if (preempt_count() == cnt)
-		trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));