Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754689AbbK0LKe (ORCPT ); Fri, 27 Nov 2015 06:10:34 -0500 Received: from mx2.suse.de ([195.135.220.15]:47656 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753963AbbK0LJz (ORCPT ); Fri, 27 Nov 2015 06:09:55 -0500 From: Petr Mladek To: Andrew Morton Cc: Peter Zijlstra , Steven Rostedt , Russell King , Daniel Thompson , Jiri Kosina , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, adi-buildroot-devel@lists.sourceforge.net, linux-cris-kernel@axis.com, linux-mips@linux-mips.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, Petr Mladek Subject: [PATCH v2 5/5] printk/nmi: Increase the size of the temporary buffer Date: Fri, 27 Nov 2015 12:09:32 +0100 Message-Id: <1448622572-16900-6-git-send-email-pmladek@suse.com> X-Mailer: git-send-email 1.8.5.6 In-Reply-To: <1448622572-16900-1-git-send-email-pmladek@suse.com> References: <1448622572-16900-1-git-send-email-pmladek@suse.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1335 Lines: 36 Testing has shown that the backtrace sometimes does not fit into the 4kB temporary buffer that is used in NMI context. The warnings are gone when I double the temporary buffer size. Note that this problem existed even in the x86-specific implementation that was added by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). Nobody noticed it because it did not print any warnings. Signed-off-by: Petr Mladek --- kernel/printk/nmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/printk/nmi.c b/kernel/printk/nmi.c index 8af1e4016719..6111644d5f01 100644 --- a/kernel/printk/nmi.c +++ b/kernel/printk/nmi.c @@ -42,7 +42,7 @@ atomic_t nmi_message_lost; struct nmi_seq_buf { atomic_t len; /* length of written data */ struct irq_work work; /* IRQ work that flushes the buffer */ - unsigned char buffer[PAGE_SIZE - sizeof(atomic_t) - + unsigned char buffer[2 * PAGE_SIZE - sizeof(atomic_t) - sizeof(struct irq_work)]; }; static DEFINE_PER_CPU(struct nmi_seq_buf, nmi_print_seq); -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/