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kernel/crash: handle multi-page vmcoreinfo in crash kernel copy

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kimage_crash_copy_vmcoreinfo() currently assumes vmcoreinfo fits in a
single page.  This breaks if VMCOREINFO_BYTES exceeds PAGE_SIZE.

Allocate the required order of control pages and vmap all pages needed to
safely copy vmcoreinfo into the crash kernel image.

Link: https://lkml.kernel.org/r/20251216132801.807260-3-pnina.feder@mobileye.com
Signed-off-by: Pnina Feder <pnina.feder@mobileye.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Pnina Feder 2025-12-16 15:28:01 +02:00 • committed by Andrew Morton
parent 76103d1b26
commit b5bfcc1ffe
1 changed files with 13 additions and 4 deletions
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17
kernel/crash_core.c
View file

@ -44,9 +44,15 @@ note_buf_t __percpu *crash_notes;
int kimage_crash_copy_vmcoreinfo(struct kimage *image)
{
struct page *vmcoreinfo_page;
struct page *vmcoreinfo_base;
struct page *vmcoreinfo_pages[DIV_ROUND_UP(VMCOREINFO_BYTES, PAGE_SIZE)];
unsigned int order, nr_pages;
int i;
void *safecopy;
nr_pages = DIV_ROUND_UP(VMCOREINFO_BYTES, PAGE_SIZE);
order = get_order(VMCOREINFO_BYTES);
if (!IS_ENABLED(CONFIG_CRASH_DUMP))
return 0;
if (image->type != KEXEC_TYPE_CRASH)
@ -61,12 +67,15 @@ int kimage_crash_copy_vmcoreinfo(struct kimage *image)
* happens to generate vmcoreinfo note, hereby we rely on
* vmap for this purpose.
*/
vmcoreinfo_page = kimage_alloc_control_pages(image, 0);
if (!vmcoreinfo_page) {
vmcoreinfo_base = kimage_alloc_control_pages(image, order);
if (!vmcoreinfo_base) {
pr_warn("Could not allocate vmcoreinfo buffer\n");
return -ENOMEM;
}
safecopy = vmap(&vmcoreinfo_page, 1, VM_MAP, PAGE_KERNEL);
for (i = 0; i < nr_pages; i++)
vmcoreinfo_pages[i] = vmcoreinfo_base + i;
safecopy = vmap(vmcoreinfo_pages, nr_pages, VM_MAP, PAGE_KERNEL);
if (!safecopy) {
pr_warn("Could not vmap vmcoreinfo buffer\n");
return -ENOMEM;