linux-kernel - [PATCH] printk: Ensure oops printing if console is locked

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Message-ID: <1339599068-25215-1-git-send-email-aurelien.gerault-xsig@stericsson.com>
Date:	Wed, 13 Jun 2012 16:51:08 +0200
From:	Aurelien Gerault <aurelien.gerault-xsig@...ricsson.com>
To:	<linux-kernel@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Aurelien Gerault <aurelien.gerault-nonst@...ricsson.com>
Subject: [PATCH] printk: Ensure oops printing if console is locked

From: Aurelien Gerault <aurelien.gerault-nonst@...ricsson.com>

Ensuring that oops & panic messages/backtraces will be printed
in console, even when the console is locked.

If console is locked by someone else but an oops is ongoing, force
unlocking / re-locking to display the oops.

Signed-off-by: Aurelien Gerault <aurelien.gerault-nonst@...ricsson.com>
---
 kernel/printk.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/printk.c b/kernel/printk.c
index 6d24237..be2a625 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1014,6 +1014,11 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 	 */
 	if (console_trylock_for_printk(this_cpu))
 		console_unlock();
+	else if (oops_in_progress) {
+		/* force releasing / acquiring console lock to print oops */
+		console_unlock();
+		console_lock();
+	}
 
 	lockdep_on();
 out_restore_irqs:
-- 
1.7.10

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