From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759655AbcLAN5y (ORCPT ); Thu, 1 Dec 2016 08:57:54 -0500 Received: from mail-pg0-f67.google.com ([74.125.83.67]:34793 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759636AbcLAN5t (ORCPT ); Thu, 1 Dec 2016 08:57:49 -0500 From: Sergey Senozhatsky To: Andrew Morton , Petr Mladek Cc: Jan Kara , Tejun Heo , Calvin Owens , Thomas Gleixner , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Andy Lutomirski , Linus Torvalds , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [RFC][PATCHv5 4/7] printk: always use deferred printk when flush printk_safe lines Date: Thu, 1 Dec 2016 22:55:43 +0900 Message-Id: <20161201135546.15549-5-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161201135546.15549-1-sergey.senozhatsky@gmail.com> References: <20161201135546.15549-1-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Sergey Senozhatsky Suggested-by: Petr Mladek --- kernel/printk/printk_safe.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index c22e286..3ded9e1 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -100,14 +100,12 @@ static int printk_safe_log_store(struct printk_safe_seq_buf *s, static 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_deferred("%.*s", len, text); } /* printk part of the temporary buffer line by line */ -- 2.10.2