Re: early exception error

Cyrill Gorcunov
2009-01-04T11:29:32Z

[Jiri Slaby - Sun, Jan 04, 2009 at 01:24:03AM +0100]
| On 01/03/2009 10:24 PM, Cyrill Gorcunov wrote:
| > [Cyrill Gorcunov - Sat, Jan 03, 2009 at 10:03:16PM +0300]
| > | (list restored)
| > |
| > | [david@lang.hm - Sat, Jan 03, 2009 at 11:19:00AM -0800]
| > | ...
| > | >>>
| > | >>> two new screenshots at http://linux.lang.hm/linux
| > | >>>
| > | >>> 36 is a boot with just earlyprintk=vga
| > | >>> 37 is a boot with numa=noacpi
| > | >>> I also put the vmlinux file there, I'll put the System.map and config
| > | >>> there later (I did enable kernel_debug on this build as well)
| > | >>>
| > | >>> David Lang
| > | >>>
| > | >>
| > | >> David, I can't find vmlinux neither .config?
| > | >> Maybe they have hidden attribute?
| > |
| > | ok, according to failing address we've a BUG_ON
| > | triggered
| > |
| > | ---
| > | (gdb) l *0xffffffff8096452a
| > | 0xffffffff8096452a is in alloc_bootmem_core (mm/bootmem.c:442).
| > | 437 unsigned long fallback = 0;
| > | 438 unsigned long min, max, start, sidx, midx, step;
| > | 439
| > | 440 BUG_ON(!size);
| > | 441 BUG_ON(align & (align - 1));
| > | 442 BUG_ON(limit && goal + size > limit);
| > | 443
| > | 444 if (!bdata->node_bootmem_map)
| > | 445 return NULL;
| > | 446
| > | (gdb)
| > | ---
| > |
| > | so we're in attempt to overrun 'limit'.
| > | Hmm...
| > |
| > | - Cyrill -
| >
| > Hardly possible that we trigger BUG here since I don't
| > see BUG: on the photo. Investigating.
|
| Hint: line 442 in 2.6.28 is
| if (!bdata->node_bootmem_map)
| ;)
|
| It's:
| 0xffffffff8096452a <alloc_bootmem_core+69>: cmpq $0x0,0x10(%rbp)
| and hence cr2 is 10.
|
| node_data[nid] is NULL... But both of them are set up. Maybe too high nid (and
| pnum in sparse_init)?
|

David, could you give it a try?

- Cyrill -
---
include/linux/mmzone.h | 1 +
1 file changed, 1 insertion(+)

Index: linux-2.6.git/include/linux/mmzone.h
===================================================================
--- linux-2.6.git.orig/include/linux/mmzone.h
+++ linux-2.6.git/include/linux/mmzone.h
@@ -980,6 +980,7 @@ extern struct mem_section mem_section[NR

static inline struct mem_section *__nr_to_section(unsigned long nr)
{
+ BUG_ON(SECTION_NR_TO_ROOT(nr) >= NR_SECTION_ROOTS);
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
return NULL;
return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];