From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757869AbcH3QOs (ORCPT ); Tue, 30 Aug 2016 12:14:48 -0400 Received: from mail-pa0-f66.google.com ([209.85.220.66]:34866 "EHLO mail-pa0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755803AbcH3QOq (ORCPT ); Tue, 30 Aug 2016 12:14:46 -0400 From: Sergey Senozhatsky To: Petr Mladek Cc: Andrew Morton , Jan Kara , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [PATCH v2] printk/nmi: avoid direct printk()-s from __printk_nmi_flush() Date: Wed, 31 Aug 2016 01:13:54 +0900 Message-Id: <20160830161354.581-1-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sergey Senozhatsky __printk_nmi_flush() can be called from nmi_panic(), therefore it has to test whether it's executed in NMI context and thus must route the messages through deferred printk() or via direct printk(). Except for two places where __printk_nmi_flush() does unconditional direct printk() calls: - pr_err("printk_nmi_flush: internal error ...") - pr_cont("\n") Factor out print_nmi_seq_line() parts into a new printk_nmi_flush_line() function, which takes care of in_nmi(), and use it in __printk_nmi_flush() for printing and error-reporting. Signed-off-by: Sergey Senozhatsky --- kernel/printk/nmi.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-) diff --git a/kernel/printk/nmi.c b/kernel/printk/nmi.c index b69eb8a..16bab47 100644 --- a/kernel/printk/nmi.c +++ b/kernel/printk/nmi.c @@ -99,27 +99,33 @@ again: return add; } -/* - * printk one line from the temporary buffer from @start index until - * and including the @end index. - */ -static void print_nmi_seq_line(struct nmi_seq_buf *s, int start, int end) +static void printk_nmi_flush_line(const char *text, int len) { - const char *buf = s->buffer + start; - /* * 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. */ if (in_nmi()) - printk_deferred("%.*s", (end - start) + 1, buf); + printk_deferred("%.*s", len, text); else - printk("%.*s", (end - start) + 1, buf); + printk("%.*s", len, text); } /* + * printk one line from the temporary buffer from @start index until + * and including the @end index. + */ +static void printk_nmi_flush_seq_line(struct nmi_seq_buf *s, + int start, int end) +{ + const char *buf = s->buffer + start; + + printk_nmi_flush_line(buf, (end - start) + 1); +} + +/* * Flush data from the associated per_CPU buffer. The function * can be called either via IRQ work or independently. */ @@ -150,9 +156,11 @@ more: * the buffer an unexpected way. If we printed something then * @len must only increase. */ - if (i && i >= len) - pr_err("printk_nmi_flush: internal error: i=%d >= len=%zu\n", - i, len); + if (i && i >= len) { + const char *msg = "printk_nmi_flush: internal error\n"; + + printk_nmi_flush_line(msg, strlen(msg)); + } if (!len) goto out; /* Someone else has already flushed the buffer. */ @@ -166,14 +174,14 @@ more: /* Print line by line. */ for (; i < size; i++) { if (s->buffer[i] == '\n') { - print_nmi_seq_line(s, last_i, i); + printk_nmi_flush_seq_line(s, last_i, i); last_i = i + 1; } } /* Check if there was a partial line. */ if (last_i < size) { - print_nmi_seq_line(s, last_i, size - 1); - pr_cont("\n"); + printk_nmi_flush_seq_line(s, last_i, size - 1); + printk_nmi_flush_line("\n", strlen("\n")); } /* -- 2.9.3