This is a note to let you know that I've just added the patch titled
Revert "mm: Always release pages to the buddy allocator in memblock_free_late()."
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
revert-mm-always-release-pages-to-the-buddy-allocator-in-memblock_free_late.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 647037adcad00f2bab8828d3d41cd0553d41f3bd Mon Sep 17 00:00:00 2001
From: Aaron Thompson <dev@xxxxxxxxxx>
Date: Tue, 7 Feb 2023 08:21:51 +0000
Subject: Revert "mm: Always release pages to the buddy allocator in memblock_free_late()."
From: Aaron Thompson <dev@xxxxxxxxxx>
commit 647037adcad00f2bab8828d3d41cd0553d41f3bd upstream.
This reverts commit 115d9d77bb0f9152c60b6e8646369fa7f6167593.
The pages being freed by memblock_free_late() have already been
initialized, but if they are in the deferred init range,
__free_one_page() might access nearby uninitialized pages when trying to
coalesce buddies. This can, for example, trigger this BUG:
BUG: unable to handle page fault for address: ffffe964c02580c8
RIP: 0010:__list_del_entry_valid+0x3f/0x70
<TASK>
__free_one_page+0x139/0x410
__free_pages_ok+0x21d/0x450
memblock_free_late+0x8c/0xb9
efi_free_boot_services+0x16b/0x25c
efi_enter_virtual_mode+0x403/0x446
start_kernel+0x678/0x714
secondary_startup_64_no_verify+0xd2/0xdb
</TASK>
A proper fix will be more involved so revert this change for the time
being.
Fixes: 115d9d77bb0f ("mm: Always release pages to the buddy allocator in memblock_free_late().")
Signed-off-by: Aaron Thompson <dev@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230207082151.1303-1-dev@xxxxxxxxxx
Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/memblock.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1615,13 +1615,7 @@ void __init __memblock_free_late(phys_ad
end = PFN_DOWN(base + size);
for (; cursor < end; cursor++) {
- /*
- * Reserved pages are always initialized by the end of
- * memblock_free_all() (by memmap_init() and, if deferred
- * initialization is enabled, memmap_init_reserved_pages()), so
- * these pages can be released directly to the buddy allocator.
- */
- __free_pages_core(pfn_to_page(cursor), 0);
+ memblock_free_pages(pfn_to_page(cursor), cursor, 0);
totalram_pages_inc();
}
}
Patches currently in stable-queue which might be from dev@xxxxxxxxxx are
queue-5.15/revert-mm-always-release-pages-to-the-buddy-allocator-in-memblock_free_late.patch
