On 07/11/2017 06:15 PM, Andrey Ryabinin wrote: > > I reproduced this, and this is kasan bug: > > │0xffffffff84864897 <x86_early_init_platform_quirks+5> mov $0xffffffff83f1d0b8,%rdi > │0xffffffff8486489e <x86_early_init_platform_quirks+12> movabs $0xdffffc0000000000,%rax > │0xffffffff848648a8 <x86_early_init_platform_quirks+22> push %rbp > │0xffffffff848648a9 <x86_early_init_platform_quirks+23> mov %rdi,%rdx > │0xffffffff848648ac <x86_early_init_platform_quirks+26> shr $0x3,%rdx > │0xffffffff848648b0 <x86_early_init_platform_quirks+30> mov %rsp,%rbp > >│0xffffffff848648b3 <x86_early_init_platform_quirks+33> mov (%rdx,%rax,1),%al > > we crash on the last move which is a read from shadow Ughh, I forgot about phys_base. Plus, I added KASAN_SANITIZE_paravirt.o :=n because with PARAVIRTY=y set_pgd() calls native_set_pgd() from paravirt.c translation unit. --- arch/x86/kernel/Makefile | 1 + arch/x86/mm/kasan_init_64.c | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 4b994232cb57..5a1f18b87fb2 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -24,6 +24,7 @@ KASAN_SANITIZE_head$(BITS).o := n KASAN_SANITIZE_dumpstack.o := n KASAN_SANITIZE_dumpstack_$(BITS).o := n KASAN_SANITIZE_stacktrace.o := n +KASAN_SANITIZE_paravirt.o := n OBJECT_FILES_NON_STANDARD_head_$(BITS).o := y OBJECT_FILES_NON_STANDARD_relocate_kernel_$(BITS).o := y diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c index d79a7ea83d05..d5743fd37df9 100644 --- a/arch/x86/mm/kasan_init_64.c +++ b/arch/x86/mm/kasan_init_64.c @@ -72,7 +72,8 @@ static void __init kasan_early_p4d_populate(pgd_t *pgd, * TODO: we need helpers for this shit */ if (CONFIG_PGTABLE_LEVELS == 5) - p4d = ((p4d_t*)((__pa_nodebug(pgd->pgd) & PTE_PFN_MASK) + __START_KERNEL_map)) + p4d = ((p4d_t*)((__pa_nodebug(pgd->pgd) & PTE_PFN_MASK) + + __START_KERNEL_map - phys_base)) + p4d_index(addr); else p4d = (p4d_t*)pgd; -- 2.13.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
