The end parameter received by kimage_is_destination_range() should be the
last valid byte address of the target memory segment plus 1. However, in
the locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions,
the corresponding value passed to kimage_is_destination_range() is the last
valid byte address of the target memory segment, which is 1 less.
There are two ways to fix this bug. We can either correct the logic of the
locate_mem_hole_bottom_up() and locate_mem_hole_top_down() functions, or we
can fix kimage_is_destination_range() by making the end parameter represent
the last valid byte address of the target memory segment. Here, we choose
the second approach.
Due to the modification to kimage_is_destination_range(), we also need to
adjust its callers, such as kimage_alloc_normal_control_pages() and
kimage_alloc_page().
Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
---
v1->v2:
Fix this issue using the approach suggested by Eric and Baoquan.
As this patch is independent of the other patches in this series, I sent
out the v2 patch separately. If it's inconvenient for anyone, I can
resend the entire series again.
v2->v3:
Modify the assignment of eaddr as suggested by Baoquan.
v3->v4:
`eaddr = epfn << PAGE_SHIFT - 1` causes a compilation warning, fix it.
kernel/kexec_core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index be5642a4ec49..e3b1a699f087 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -276,8 +276,8 @@ int kimage_is_destination_range(struct kimage *image,
unsigned long mstart, mend;
mstart = image->segment[i].mem;
- mend = mstart + image->segment[i].memsz;
- if ((end > mstart) && (start < mend))
+ mend = mstart + image->segment[i].memsz - 1;
+ if ((end >= mstart) && (start <= mend))
return 1;
}
@@ -370,7 +370,7 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image,
pfn = page_to_boot_pfn(pages);
epfn = pfn + count;
addr = pfn << PAGE_SHIFT;
- eaddr = epfn << PAGE_SHIFT;
+ eaddr = (epfn << PAGE_SHIFT) - 1;
if ((epfn >= (KEXEC_CONTROL_MEMORY_LIMIT >> PAGE_SHIFT)) ||
kimage_is_destination_range(image, addr, eaddr)) {
list_add(&pages->lru, &extra_pages);
@@ -716,7 +716,7 @@ static struct page *kimage_alloc_page(struct kimage *image,
/* If the page is not a destination page use it */
if (!kimage_is_destination_range(image, addr,
- addr + PAGE_SIZE))
+ addr + PAGE_SIZE - 1))
break;
/*
--
2.43.0
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