On 2024/4/11 17:59, Catalin Marinas wrote:
On Wed, Apr 10, 2024 at 06:58:27PM +0800, Kefeng Wang wrote:
On 2024/4/10 9:30, Kefeng Wang wrote:
On 2024/4/9 22:28, Catalin Marinas wrote:
On Sun, Apr 07, 2024 at 04:12:10PM +0800, Kefeng Wang wrote:
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 405f9aa831bd..61a2acae0dca 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -500,9 +500,6 @@ static bool is_write_abort(unsigned long esr)
return (esr & ESR_ELx_WNR) && !(esr & ESR_ELx_CM);
}
-#define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000)
-#define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
-
static int __kprobes do_page_fault(unsigned long far, unsigned
long esr,
struct pt_regs *regs)
{
@@ -513,6 +510,7 @@ static int __kprobes do_page_fault(unsigned
long far, unsigned long esr,
unsigned int mm_flags = FAULT_FLAG_DEFAULT;
unsigned long addr = untagged_addr(far);
struct vm_area_struct *vma;
+ int si_code;
I think we should initialise this to 0. Currently all paths seem to set
si_code to something meaningful but I'm not sure the last 'else' close
in this patch is guaranteed to always cover exactly those earlier code
paths updating si_code. I'm not talking about the 'goto bad_area' paths
since they set 'fault' to 0 but the fall through after the second (under
the mm lock) handle_mm_fault().
[...]
+ fault = handle_mm_fault(vma, addr, mm_flags, regs);
/* Quick path to respond to signals */
if (fault_signal_pending(fault, regs)) {
if (!user_mode(regs))
@@ -626,13 +628,11 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr,
mmap_read_unlock(mm);
done:
- /*
- * Handle the "normal" (no error) case first.
- */
- if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP |
- VM_FAULT_BADACCESS))))
+ /* Handle the "normal" (no error) case first. */
+ if (likely(!(fault & VM_FAULT_ERROR)))
return 0;
Another choice, we set si_code = SEGV_MAPERR here, since normal
pagefault don't use si_code, only the error patch need to initialize.
Yes, I think initialising it here would be fine. That's the fall-through
case I was concerned about. All the other goto bad_area places already
initialise si_code.
Thanks for your confirm, will send v2 soon.
