From: Ran Xiaokai <[email protected]>
Memblock pages (including reserved memory) should have their allocation
tags initialized to CODETAG_EMPTY via clear_page_tag_ref() before being
released to the page allocator. When kho restores pages through
kho_restore_page(), missing this call causes mismatched
allocation/deallocation tracking and below warning message:
alloc_tag was not set
WARNING: include/linux/alloc_tag.h:164 at ___free_pages+0xb8/0x260, CPU#1:
swapper/0/1
RIP: 0010:___free_pages+0xb8/0x260
kho_restore_vmalloc+0x187/0x2e0
kho_test_init+0x3c4/0xa30
do_one_initcall+0x62/0x2b0
kernel_init_freeable+0x25b/0x480
kernel_init+0x1a/0x1c0
ret_from_fork+0x2d1/0x360
Add missing clear_page_tag_ref() annotation in kho_restore_page() to
fix this.
Fixes: fc33e4b44b27 ("kexec: enable KHO support for memory preservation")
Cc: <[email protected]>
Signed-off-by: Ran Xiaokai <[email protected]>
---
v2 -> v3:
- also call clear_page_tag_ref() for non-compound order-0 tail pages
kernel/liveupdate/kexec_handover.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/kernel/liveupdate/kexec_handover.c
b/kernel/liveupdate/kexec_handover.c
index d4482b6e3cae..96767b106cac 100644
--- a/kernel/liveupdate/kexec_handover.c
+++ b/kernel/liveupdate/kexec_handover.c
@@ -255,6 +255,14 @@ static struct page *kho_restore_page(phys_addr_t phys,
bool is_folio)
if (is_folio && info.order)
prep_compound_page(page, info.order);
+ /* Always mark headpage's codetag as empty to avoid accounting mismatch
*/
+ clear_page_tag_ref(page);
+ if (!is_folio) {
+ /* Also do that for the non-compound tail pages */
+ for (unsigned int i = 1; i < nr_pages; i++)
+ clear_page_tag_ref(page + i);
+ }
+
adjust_managed_page_count(page, nr_pages);
return page;
}
--
2.25.1
