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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>, Jan Kara <jack@suse.com>,
	Tejun Heo <tj@kernel.org>, Kyle McMartin <kyle@kernel.org>,
	Dave Jones <davej@codemonkey.org.uk>,
	Calvin Owens <calvinowens@fb.com>,
	linux-kernel@vger.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: [PATCH v4 3/3] printk: check CON_ENABLED in have_callable_console()
Date: Sat, 13 Feb 2016 03:37:12 +0900	[thread overview]
Message-ID: <1455302232-2252-4-git-send-email-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <1455302232-2252-1-git-send-email-sergey.senozhatsky@gmail.com>

have_callable_console() must also test CON_ENABLED bit, not just
CON_ANYTIME. We may have disabled CON_ANYTIME console so printk
can wrongly assume that it's safe to call_console_drivers().

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 kernel/printk/printk.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 9f0c3e1..9917f69 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2139,7 +2139,8 @@ static int have_callable_console(void)
 	struct console *con;
 
 	for_each_console(con)
-		if (con->flags & CON_ANYTIME)
+		if ((con->flags & CON_ENABLED) &&
+				(con->flags & CON_ANYTIME))
 			return 1;
 
 	return 0;
-- 
2.7.1

  parent reply	other threads:[~2016-02-12 18:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-12 18:37 [PATCH v4 0/2] let printk()/console_trylock() callers to cond_resched() Sergey Senozhatsky
2016-02-12 18:37 ` [PATCH v4 1/3] printk: move can_use_console out of console_trylock_for_printk Sergey Senozhatsky
2016-02-12 18:37 ` [PATCH v4 2/3] printk: set may_schedule for some of console_trylock callers Sergey Senozhatsky
2016-02-16 14:43   ` Petr Mladek
2016-02-16 15:45     ` Sergey Senozhatsky
2016-02-12 18:37 ` Sergey Senozhatsky [this message]
2016-02-16 14:44   ` [PATCH v4 3/3] printk: check CON_ENABLED in have_callable_console() Petr Mladek
2016-02-16 15:44     ` Sergey Senozhatsky

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