Commit dbda92d1 authored Feb 18, 2013 by Bu, Yitian Committed by Thomas Gleixner Feb 18, 2013

printk: Fix rq->lock vs logbuf_lock unlock lock inversion



commit 07354eb1 ("locking printk: Annotate logbuf_lock as raw")
reintroduced a lock inversion problem which was fixed in commit
0b5e1c52 ("printk: Release console_sem after logbuf_lock"). This
happened probably when fixing up patch rejects.

Restore the ordering and unlock logbuf_lock before releasing
console_sem.

Signed-off-by: ybu <ybu@qti.qualcomm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/E807E903FE6CBE4D95E420FBFCC273B827413C@nasanexd01h.na.qualcomm.com


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent 211b0cdc

kernel/printk.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1358,9 +1358,9 @@ static int console_trylock_for_printk(unsigned int cpu)
	}		}
	}		}
	logbuf_cpu = UINT_MAX;		logbuf_cpu = UINT_MAX;
			raw_spin_unlock(&logbuf_lock);
	if (wake)		if (wake)
	up(&console_sem);		up(&console_sem);
	raw_spin_unlock(&logbuf_lock);
	return retval;		return retval;
	}		}