Re: 2.6.26-rc5-mm1: uml link error

From: Peter Oberparleiter
Date: Tue Jun 10 2008 - 10:22:18 EST


Peter 1 Oberparleiter wrote:
> Jeff Dike <jdike@xxxxxxxxxxx> wrote on 10.06.2008 15:57:29:
>
>> On Tue, Jun 10, 2008 at 01:19:27PM +0200, Miklos Szeredi wrote:
>> > Hmm, uml still doesn't boot with this patch, it dies while calling the
>> > constructors. So maybe that SORT contruct is still needed?
>> >
>> > #17 0x08049793 in do_ctors () at init/main.c:706
>> > #18 0x080499cc in do_basic_setup () at init/main.c:789
>> > #19 0x08049a43 in kernel_init (unused=0x0) at init/main.c:897
>>
>> This doesn't look like it's in do_initcalls. What happens with
>> "initcall_debug"?
>
> Constructor calls inside the kernel happen just before any other
> initcall. The problem here is that constructors are called from both
> the host run-time environment as well as from the kernel. I'm
> working on a patch that disables kernel constructor calling for UML.

New try: should be fixed with the patch below (applies on top of
kernel-call-constructors.patch):

--
Subject: kernel: disable constructor calling for uml

From: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>

Disable calling of constructor functions from within the kernel for uml
as they are already called by the host run-time environment.

Found-by: Miklos Szeredi <miklos@xxxxxxxxxx>
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@xxxxxxxxxx>
---
include/asm-generic/vmlinux.lds.h | 2 ++
init/main.c | 2 ++
kernel/module.c | 2 ++
3 files changed, 6 insertions(+)

Index: linux-2.6.26-rc5-mm2/include/asm-generic/vmlinux.lds.h
===================================================================
--- linux-2.6.26-rc5-mm2.orig/include/asm-generic/vmlinux.lds.h
+++ linux-2.6.26-rc5-mm2/include/asm-generic/vmlinux.lds.h
@@ -381,7 +381,9 @@
} \
__per_cpu_end = .;

+#ifndef CONFIG_UML
#define CONSTRUCTORS \
VMLINUX_SYMBOL(__ctor_start) = .; \
*(.ctors) \
VMLINUX_SYMBOL(__ctor_end) = .;
+#endif /* !CONFIG_UML */
Index: linux-2.6.26-rc5-mm2/init/main.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/init/main.c
+++ linux-2.6.26-rc5-mm2/init/main.c
@@ -699,11 +699,13 @@ asmlinkage void __init start_kernel(void

static void __init do_ctors(void)
{
+#ifndef CONFIG_UML
ctorcall_t *call;

for (call = (ctorcall_t *) __ctor_start;
call < (ctorcall_t *) __ctor_end; call++)
(*call)();
+#endif /* !CONFIG_UML */
}

static int __initdata initcall_debug;
Index: linux-2.6.26-rc5-mm2/kernel/module.c
===================================================================
--- linux-2.6.26-rc5-mm2.orig/kernel/module.c
+++ linux-2.6.26-rc5-mm2/kernel/module.c
@@ -2194,10 +2194,12 @@ static struct module *load_module(void _

static void do_mod_ctors(struct module *mod)
{
+#ifndef CONFIG_UML
unsigned long i;

for (i = 0; i < mod->num_ctors; i++)
mod->ctors[i]();
+#endif /* !CONFIG_UML */
}

/* This is where the real work happens */
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