On [jeu., 18.04.2013 16:23:39], Gregory CLEMENT wrote:
> 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 <gregory.clem...@free-electrons.com>
> ---
> 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
Tested on at91sam9g35-ek kernel 3.9-rc7 +custom patches
Tested-by: Richard Genoud <richard.gen...@gmail.com>
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