From: Andrew Morton <akpm@linux-foundation.org>
To: Chandru <chandru@in.ibm.com>
Cc: Benjamin, linuxppc-dev@ozlabs.org,
Paul Mackerras <paulus@samba.org>,
linux-kernel@vger.kernel.org
Subject: Re: 2.6.28-rc9 panics with crashkernel=256M while booting
Date: Wed, 24 Dec 2008 23:35:36 -0800 [thread overview]
Message-ID: <20081224233536.b067c9da.akpm@linux-foundation.org> (raw)
In-Reply-To: <200812241325.49404.chandru@in.ibm.com>
(cc's added)
On Wed, 24 Dec 2008 13:25:49 +0530 Chandru <chandru@in.ibm.com> wrote:
> On a ppc machine booting linux-2.6.28-rc9 with crashkernel=256M@32M boot
> parameter causes the kernel to panic while booting. __Following are the console
> messages...
- Please put [patch] in the Subject: line of patches
- Please choose a suitable title, as per
Documentation/SubmittingPatches, section 15.
- Please cc suitable mailing lists and maintainers on bug reports and
on patches.
From: Chandru <chandru@in.ibm.com>
When booted with crashkernel=224M@32M or any memory size less than this,
the system boots properly. The following was the observation.. The
system comes up with two nodes (0-256M and 256M-4GB). _The crashkernel
memory reservation spans across these two nodes. _The
mark_reserved_regions_for_nid() in arch/powerpc/mm/numa.c resizes the
reserved part of the memory within it as:
_ _ _ _ _ _ if (end_pfn > node_ar.end_pfn)
_ _ _ _ _ _ _ _ reserve_size = (node_ar.end_pfn << PAGE_SHIFT)
_ _ _ _ _ _ _ _ _ _ - (start_pfn << PAGE_SHIFT);
but the reserve_bootmem_node() in mm/bootmem.c raises the pfn value of end
_ _ end = PFN_UP(physaddr + size);
This causes end to get a value past the last page in the 0-256M node.
_Again when reserve_bootmem_node() returns,
_mark_reserved_regions_for_nid() loops around to set the rest of the
crashkernel memory in the next node as reserved. _ It references
NODE_DATA(node_ar.nid) and this causes another 'Oops: kernel access of bad
area' problem. The following changes made the system to boot with any
amount of crashkernel memory size.
Signed-off-by: Chandru S <chandru@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/powerpc/mm/numa.c | 7 ++++---
mm/bootmem.c | 4 ++++
2 files changed, 8 insertions(+), 3 deletions(-)
diff -puN arch/powerpc/mm/numa.c~2628-rc9-panics-with-crashkernel=256m-while-booting arch/powerpc/mm/numa.c
--- a/arch/powerpc/mm/numa.c~2628-rc9-panics-with-crashkernel=256m-while-booting
+++ a/arch/powerpc/mm/numa.c
@@ -995,10 +995,11 @@ void __init do_init_bootmem(void)
start_pfn, end_pfn);
free_bootmem_with_active_regions(nid, end_pfn);
+ }
+
+ for_each_online_node(nid) {
/*
- * Be very careful about moving this around. Future
- * calls to careful_allocation() depend on this getting
- * done correctly.
+ * Be very careful about moving this around.
*/
mark_reserved_regions_for_nid(nid);
sparse_memory_present_with_active_regions(nid);
diff -puN mm/bootmem.c~2628-rc9-panics-with-crashkernel=256m-while-booting mm/bootmem.c
--- a/mm/bootmem.c~2628-rc9-panics-with-crashkernel=256m-while-booting
+++ a/mm/bootmem.c
@@ -375,10 +375,14 @@ int __init reserve_bootmem_node(pg_data_
unsigned long size, int flags)
{
unsigned long start, end;
+ bootmem_data_t *bdata = pgdat->bdata;
start = PFN_DOWN(physaddr);
end = PFN_UP(physaddr + size);
+ if (end > bdata->node_low_pfn)
+ end = bdata->node_low_pfn;
+
return mark_bootmem_node(pgdat->bdata, start, end, 1, flags);
}
_
next parent reply other threads:[~2008-12-25 7:36 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200812241325.49404.chandru@in.ibm.com>
2008-12-25 7:35 ` Andrew Morton [this message]
2008-12-25 8:07 ` 2.6.28-rc9 panics with crashkernel=256M while booting Andrew Morton
2008-12-26 0:59 ` Paul Mackerras
2008-12-29 21:36 ` Dave Hansen
2009-01-05 13:49 ` Chandru
2009-01-05 16:30 ` Dave Hansen
2009-01-07 12:58 ` Chandru
2009-01-07 17:25 ` Dave Hansen
2009-01-08 10:29 ` Chandru
2009-01-08 20:03 ` Dave Hansen
2009-01-09 11:07 ` Chandru
2009-01-15 8:05 ` Chandru
2009-01-16 12:16 ` Chandru
2009-01-16 17:52 ` Dave Hansen
2009-01-19 8:11 ` Chandru
2009-01-19 11:30 ` Chandru
2009-01-20 8:13 ` Chandru
2009-01-22 0:29 ` Dave Hansen
2009-01-22 8:20 ` Chandru
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