softirq/preempt: Add missing current->preempt_disable_ip update
authorHeiko Carstens <heiko.carstens@de.ibm.com>
Wed, 7 Jan 2015 09:04:41 +0000 (10:04 +0100)
committerIngo Molnar <mingo@kernel.org>
Wed, 14 Jan 2015 14:16:21 +0000 (15:16 +0100)
commit0f1ba9a2cea52896448ef4e14a4cb1880b8e5bee
tree301b6a4c78620715ea99a35eba30e80a866097e9
parent036cc30c6b6af1cd42de6c34c4461f17da01cbf7
softirq/preempt: Add missing current->preempt_disable_ip update

While debugging some "sleeping function called from invalid context" bug I
realized that the debugging message "Preemption disabled at:" pointed to
an incorrect function.

In particular if the last 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 <heiko.carstens@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20150107090441.GC4365@osiris
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/softirq.c