Commit 7acac344 authored Feb 07, 2017 by Sergey Senozhatsky Committed by Petr Mladek Feb 08, 2017

printk: always use deferred printk when flush printk_safe lines

Always use printk_deferred() in printk_safe_flush_line().
Flushing can be done from NMI or printk_safe contexts (when
we are in panic), so we can't call console drivers, yet still
want to store the messages in the logbuf buffer. Therefore we
use a deferred printk version.

Link: http://lkml.kernel.org/r/20170206164253.GA463@tigerII.localdomain


Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Calvin Owens <calvinowens@fb.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent 099f1c84

kernel/printk/printk_safe.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -110,17 +110,15 @@ static int printk_safe_log_store(struct printk_safe_seq_buf *s,
		return add;
		}

		static void printk_safe_flush_line(const char *text, int len)
		static inline void printk_safe_flush_line(const char *text, int len)
		{
		/*
		* The buffers are flushed in NMI only on panic. The messages must
		* go only into the ring buffer at this stage. Consoles will get
		* explicitly called later when a crashdump is not generated.
		* Avoid any console drivers calls from here, because we may be
		* in NMI or printk_safe context (when in panic). The messages
		* must go only into the ring buffer at this stage. Consoles will
		* get explicitly called later when a crashdump is not generated.
		*/
		if (in_nmi())
		printk_deferred("%.*s", len, text);
		else
		printk("%.*s", len, text);
		}

		/* printk part of the temporary buffer line by line */