From mboxrd@z Thu Jan 1 00:00:00 1970 From: gregory.clement@free-electrons.com (Gregory CLEMENT) Date: Thu, 18 Apr 2013 16:23:39 +0200 Subject: [PATCH RFC] ARM: don't allow to register the early_console twice In-Reply-To: <1366295019-30335-1-git-send-email-gregory.clement@free-electrons.com> References: <1366295019-30335-1-git-send-email-gregory.clement@free-electrons.com> Message-ID: <1366295019-30335-2-git-send-email-gregory.clement@free-electrons.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org If on the kernel command line the parameter "earlyprintk" is written twice, then setup_early_printk is called twice. This can happen for example with the option CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND is selected, and the "earlyprintk" is passed from the ATAG_CMDLINE and from the dtb. This lead to an infinite loop on the message "Booting Linux on physical CPU 0" displayed from smp_setup_processor_id() in arch/arm/kernel/setup.c. This behavior as been reproduced on ARMv7 architecture (Armada XP and Armada 370), and on a ARMv5 one (AT91SAMG35 thanks to Richard Genoud), with and with CONFIG_SMP selected. This patch simply doesn't allow to call twice register_console() with the early_console. Signed-off-by: Gregory CLEMENT --- arch/arm/kernel/early_printk.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/early_printk.c b/arch/arm/kernel/early_printk.c index 85aa2b2..435577a 100644 --- a/arch/arm/kernel/early_printk.c +++ b/arch/arm/kernel/early_printk.c @@ -50,7 +50,11 @@ asmlinkage void early_printk(const char *fmt, ...) static int __init setup_early_printk(char *buf) { - register_console(&early_console); + static int done; + if (!done) { + register_console(&early_console); + done = 1; + } return 0; } -- 1.7.9.5