From: Christophe Leroy <christophe.leroy@xxxxxx> [ Upstream commit e033829d2aaad85cb7cf46986c3be0bcc72f791e ] walk_pagetables() always walk the entire pgdir from address 0 but considers PAGE_OFFSET or KERN_VIRT_START as the starting address of the walk, resulting in a possible mismatch in the displayed addresses. Ex: on PPC32, when KERN_VIRT_START was locally defined as PAGE_OFFSET, ptdump displayed 0x80000000 instead of 0xc0000000 for the first kernel page, because 0xc0000000 + 0xc0000000 = 0x80000000 Start the walk at st->start_address instead of starting at 0. Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/5aa2ac513295f594cce8ddb1c649f61947bd063d.1565786091.git.christophe.leroy@xxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- arch/powerpc/mm/ptdump/ptdump.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c index 6a88a9f585d4f..5d6111a9ee0e7 100644 --- a/arch/powerpc/mm/ptdump/ptdump.c +++ b/arch/powerpc/mm/ptdump/ptdump.c @@ -299,17 +299,15 @@ static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) static void walk_pagetables(struct pg_state *st) { - pgd_t *pgd = pgd_offset_k(0UL); unsigned int i; - unsigned long addr; - - addr = st->start_address; + unsigned long addr = st->start_address & PGDIR_MASK; + pgd_t *pgd = pgd_offset_k(addr); /* * Traverse the linux pagetable structure and dump pages that are in * the hash pagetable. */ - for (i = 0; i < PTRS_PER_PGD; i++, pgd++, addr += PGDIR_SIZE) { + for (i = pgd_index(addr); i < PTRS_PER_PGD; i++, pgd++, addr += PGDIR_SIZE) { if (!pgd_none(*pgd) && !pgd_is_leaf(*pgd)) /* pgd exists */ walk_pud(st, pgd, addr); -- 2.20.1
