[PATCH 1/2] [RESEND] console: use might_sleep in console_lock
Daniel Vetter
daniel.vetter at ffwll.ch
Mon Sep 17 16:03:31 PDT 2012
Instead of BUG_ON(in_interrupt()), since that doesn't check for all
the newfangled stuff like preempt.
Note that this is valid since the console_sem is essentially used like
a real mutex with only two twists:
- we allow trylock from hardirq context
- across suspend/resume we lock the logical console_lock, but drop the
semaphore protecting the locking state.
Now that doesn't guarantee that no one is playing tricks in
single-thread atomic contexts at suspend/resume/boot time, but
- I couldn't find anything suspicious with some grepping,
- might_sleep shouldn't die,
- and I think the upside of catching more potential issues is worth
the risk of getting a might_sleep backtrace that would have been
save (and then dealing with that fallout).
Cc: Dave Airlie <airlied at gmail.com>
Cc: Thomas Gleixner <tglx at linutronix.de>
Cc: Alan Cox <alan at lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra at chello.nl>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
kernel/printk.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/printk.c b/kernel/printk.c
index 66a2ea3..ed9af6a 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1909,7 +1909,8 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
*/
void console_lock(void)
{
- BUG_ON(in_interrupt());
+ might_sleep();
+
down(&console_sem);
if (console_suspended)
return;
--
1.7.10.4
More information about the dri-devel
mailing list