In commit 2865d08dd9ea876524652f3900b4b3b9c8b22e77 "powerpc/mm: Move the DSISR_PROTFAULT sanity check", I completely missed the fact that an attempt at reading kernel memory *will* trip the warning.
So this partially reverts it. We keep the test in a helper to keep the code clean, but we move it back to after the VMA has been found. Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> --- diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index c01d627e687a..20384445ca44 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -416,9 +416,6 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, return SIGBUS; } - /* Additional sanity check(s) */ - sanity_check_fault(is_write, error_code); - /* * The kernel should never take an execute fault nor should it * take a page fault to a kernel address. @@ -511,6 +508,10 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address, return bad_area(regs, address); good_area: + /* Additional sanity check(s) */ + sanity_check_fault(is_write, error_code); + + /* Check for VMA access permissions */ if (unlikely(access_error(is_write, is_exec, vma))) return bad_access(regs, address);