The accept_memory() and range_contains_unaccepted_memory() functions employ a "guard page" logic to prevent crashes with load_unaligned_zeropad(). This logic extends the range to be accepted (or checked) by one unit_size if the end of the range is aligned to a unit_size boundary. However, if the caller passes a range that is not page-aligned, the 'end' of the range might not be numerically aligned to unit_size, even if it covers the last page of a unit. This causes the "if (!(end % unit_size))" check to fail, skipping the necessary extension and leaving the next unit unaccepted, which can lead to a kernel panic when accessed by load_unaligned_zeropad(). Align the start address down and the size up to the nearest page boundary before performing the unit_size alignment check. This ensures that the guard unit is correctly added when the range effectively ends on a unit boundary. Signed-off-by: Kiryl Shutsemau (Meta) --- drivers/firmware/efi/unaccepted_memory.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/efi/unaccepted_memory.c b/drivers/firmware/efi/unaccepted_memory.c index c2c067eff634..9ddf3dedd514 100644 --- a/drivers/firmware/efi/unaccepted_memory.c +++ b/drivers/firmware/efi/unaccepted_memory.c @@ -35,14 +35,18 @@ void accept_memory(phys_addr_t start, unsigned long size) struct efi_unaccepted_memory *unaccepted; unsigned long range_start, range_end; struct accept_range range, *entry; - phys_addr_t end = start + size; unsigned long flags; + phys_addr_t end; u64 unit_size; unaccepted = efi_get_unaccepted_table(); if (!unaccepted) return; + start = PAGE_ALIGN_DOWN(start); + size = PAGE_ALIGN(size); + end = start + size; + unit_size = unaccepted->unit_size; /* @@ -160,15 +164,19 @@ void accept_memory(phys_addr_t start, unsigned long size) bool range_contains_unaccepted_memory(phys_addr_t start, unsigned long size) { struct efi_unaccepted_memory *unaccepted; - phys_addr_t end = start + size; unsigned long flags; bool ret = false; + phys_addr_t end; u64 unit_size; unaccepted = efi_get_unaccepted_table(); if (!unaccepted) return false; + start = PAGE_ALIGN_DOWN(start); + size = PAGE_ALIGN(size); + end = start + size; + unit_size = unaccepted->unit_size; /* -- 2.51.2