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Revert "mm: Always release pages to the buddy allocator in memblock_free_late()."

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This reverts commit 115d9d77bb.

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: 115d9d77bb ("mm: Always release pages to the buddy allocator in memblock_free_late().")
Signed-off-by: Aaron Thompson <dev@aaront.org>
Link: https://lore.kernel.org/r/20230207082151.1303-1-dev@aaront.org
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
This commit is contained in:
Aaron Thompson 2023-02-07 08:21:51 +00:00 committed by Mike Rapoport (IBM)
parent 4ec5183ec4
commit 647037adca
2 changed files with 1 additions and 11 deletions
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8
mm/memblock.c
View File

@ -1640,13 +1640,7 @@ void __init memblock_free_late(phys_addr_t base, phys_addr_t size)
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();
}
}

4
tools/testing/memblock/internal.h
View File

@ -15,10 +15,6 @@ bool mirrored_kernelcore = false;
struct page {};
void __free_pages_core(struct page *page, unsigned int order)
{
}
void memblock_free_pages(struct page *page, unsigned long pfn,
unsigned int order)
{