Re: Can not boot with CONFIG_NO_BOOTMEM=y on i686

[Yinghai Lu <yinghai@kernel.org>]

On 03/24/2010 02:04 AM, Stanislaw Gruszka wrote:
> On Tue, Mar 23, 2010 at 09:06:00PM -0700, Yinghai Lu wrote:
>> On 03/23/2010 04:35 AM, Stanislaw Gruszka wrote:
>>> On Sat, Mar 20, 2010 at 11:26:06AM -0700, Yinghai Lu wrote:
>>>>> After update to 2.6.34-rc1, I was experimented by strange oopses during
>>>>> boot, what looked like memory corruption. Bisection shows that first bad
>>>>> commit is 59be5a8e8ce765cf739ec7f07176219972de7481 ("x86: Make 32bit
>>>>> support NO_BOOTMEM"). When I disable CONFIG_NO_BOOTMEM I'm able to start
>>>>> system. Not sure what info is need to track down this issue, so please
>>>>> let me know.
>>>>
>>>> can you check patch
>>>>
>>>> https://patchwork.kernel.org/patch/87081/
>>>
>>> Patch helps somehow. Instead of many random oopses, now I have one and
>>> the same oops, here is photo:
>>> http://people.redhat.com/sgruszka/20100322_001.jpg
>>
>> how does e820 look like?
> 
> dmesg below, I hope everything you asked for is here:
> 
> Linux version 2.6.34-rc1 (stasiu@yellow) (gcc version 4.4.2 20091222 (Red Hat 4.4.2-20) (GCC) ) #26 SMP Tue Mar 23 11:31:22 CET 2010
> BIOS-provided physical RAM map:
>  BIOS-e820: 0000000000000000 - 0000000000096400 (usable)
>  BIOS-e820: 0000000000096400 - 00000000000a0000 (reserved)
>  BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
>  BIOS-e820: 0000000000100000 - 00000000cffc2840 (usable)
>  BIOS-e820: 00000000cffc2840 - 00000000d0000000 (reserved)
>  BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved)
>  BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)
>  BIOS-e820: 0000000100000000 - 0000000130000000 (usable)
...
> initial memory mapped : 0 - 01000000
> found SMP MP-table at [c00fe700] fe700
> init_memory_mapping: 0000000000000000-00000000373fe000
>  0000000000 - 0000400000 page 4k
>  0000400000 - 0037000000 page 2M
>  0037000000 - 00373fe000 page 4k
> kernel direct mapping tables up to 373fe000 @ 7000-d000
> RAMDISK: 373b8000 - 37fef224
> Allocated new RAMDISK: 00b2f000 - 01766224
> Move RAMDISK from 00000000373b8000 - 0000000037fef223 to 00b2f000 - 01766223
> Reserving 256MB of memory at 32MB for crashkernel (System RAM: 3327MB)

Please check if this one helps

Thanks

Yinghai

---
[PATCH] x86: Make sure free_init_pages() free pages in boundary

When CONFIG_NO_BOOTMEM, it could use memory more efficient, or more compact.

Example is:
Allocated new RAMDISK: 00ec2000 - 0248ce57
Move RAMDISK from 000000002ea04000 - 000000002ffcee56 to 00ec2000 - 0248ce56

The new RAMDISK's end is not page aligned.
Last page could use shared with other user.

When free_init_pages are called for initrd or .init, the page could be freed
could have chance to corrupt other data.

code segment in free_init_pages()
|        for (; addr < end; addr += PAGE_SIZE) {
|                ClearPageReserved(virt_to_page(addr));
|                init_page_count(virt_to_page(addr));
|                memset((void *)(addr & ~(PAGE_SIZE-1)),
|                        POISON_FREE_INITMEM, PAGE_SIZE);
|                free_page(addr);
|                totalram_pages++;
|        }
last half page could be used as one whole free page.

Try to make the boundaries to be page aligned.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/x86/mm/init.c |    4 ++++
 1 file changed, 4 insertions(+)

Index: linux-2.6/arch/x86/mm/init.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init.c
+++ linux-2.6/arch/x86/mm/init.c
@@ -334,6 +334,10 @@ void free_init_pages(char *what, unsigne
 {
 	unsigned long addr = begin;
 
+	/* Make sure boundaries are page aligned */
+	addr = PFN_UP(addr) << PAGE_SHIFT;
+	end = PFN_DOWN(end) << PAGE_SHIFT;
+
 	if (addr >= end)
 		return;