From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Date: Tue, 21 Aug 2012 22:34:31 +0000 Subject: [PATCH 1/2] console: use might_sleep in console_lock Message-Id: <1345588472-4055-2-git-send-email-daniel.vetter@ffwll.ch> List-Id: References: <1345588472-4055-1-git-send-email-daniel.vetter@ffwll.ch> In-Reply-To: <1345588472-4055-1-git-send-email-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: LKML Cc: DRI Development , linux-fbdev@vger.kernel.org, Alan Cox , Daniel Vetter , Dave Airlie , Thomas Gleixner 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 Cc: Thomas Gleixner Signed-off-by: Daniel Vetter --- 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