Messages in this thread Patch in this message | | | From | Joerg Roedel <> | Subject | [PATCH] x86/mm: Fix kernel oops in PTDUMP code with HIGHPTE=y | Date | Tue, 17 Apr 2018 15:27:16 +0200 |
| |
From: Joerg Roedel <jroedel@suse.de>
The walk_pte_level() function just uses __va to get the virtual address of the PTE page, but that breaks when the PTE page is not in the direct mapping with HIGHPTE=y.
The result is an unhandled kernel paging request at some random address when accessing the current_kernel or current_user file.
Use the correct API to access PTE pages nd fix the oops.
Fixes: fe770bf0310d ('x86: clean up the page table dumper and add 32-bit support') Signed-off-by: Joerg Roedel <jroedel@suse.de> --- arch/x86/mm/dump_pagetables.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/arch/x86/mm/dump_pagetables.c b/arch/x86/mm/dump_pagetables.c index 956c886f5dff..db1d7a0e6335 100644 --- a/arch/x86/mm/dump_pagetables.c +++ b/arch/x86/mm/dump_pagetables.c @@ -18,6 +18,7 @@ #include <linux/init.h> #include <linux/sched.h> #include <linux/seq_file.h> +#include <linux/highmem.h> #include <asm/pgtable.h> @@ -344,16 +345,16 @@ static void walk_pte_level(struct seq_file *m, struct pg_state *st, pmd_t addr, pgprotval_t eff_in, unsigned long P) { int i; - pte_t *start; + pte_t *pte; pgprotval_t prot, eff; - start = (pte_t *)pmd_page_vaddr(addr); for (i = 0; i < PTRS_PER_PTE; i++) { - prot = pte_flags(*start); - eff = effective_prot(eff_in, prot); st->current_address = normalize_addr(P + i * PTE_LEVEL_MULT); + pte = pte_offset_map(&addr, st->current_address); + prot = pte_flags(*pte); + eff = effective_prot(eff_in, prot); note_page(m, st, __pgprot(prot), eff, 5); - start++; + pte_unmap(pte); } } #ifdef CONFIG_KASAN -- 2.13.6
| |