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SubjectRe: kexec load failure introduced by "x86, memblock: Replace e820_/_early string with memblock_"
Please check this one on top of tip or next.

Thanks

Yinghai

[PATCH] x86, memblock: Fix crashkernel allocation

Cai Qian found that crashkernel is broken with x86 memblock changes
1. crashkernel=128M@32M always reported that range is used, even first kernel is small
no one use that range
2. always get following report when using "kexec -p"
Could not find a free area of memory of a000 bytes...
locate_hole failed

The root cause is that generic memblock_find_in_range() will try to get range from top_down.
But crashkernel do need from low and specified range.

Let's limit the target range with rash_base + crash_size to make sure that
We get range from bottom.

Reported-and-Bisected-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
arch/x86/kernel/setup.c | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)

Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -516,19 +516,28 @@ static void __init reserve_crashkernel(v

/* 0 means: find the address automatically */
if (crash_base <= 0) {
+ unsigned long long start = 0;
const unsigned long long alignment = 16<<20; /* 16M */

- crash_base = memblock_find_in_range(alignment, ULONG_MAX, crash_size,
- alignment);
- if (crash_base == MEMBLOCK_ERROR) {
+ crash_base = alignment;
+ while (crash_base < 0xffffffff) {
+ start = memblock_find_in_range(crash_base,
+ crash_base + crash_size, crash_size, alignment);
+
+ if (start == crash_base)
+ break;
+
+ crash_base += alignment;
+ }
+ if (start != crash_base) {
pr_info("crashkernel reservation failed - No suitable area found.\n");
return;
}
} else {
unsigned long long start;

- start = memblock_find_in_range(crash_base, ULONG_MAX, crash_size,
- 1<<20);
+ start = memblock_find_in_range(crash_base,
+ crash_base + crash_size, crash_size, 1<<20);
if (start != crash_base) {
pr_info("crashkernel reservation failed - memory is in use.\n");
return;

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