On Tue, 9 Jan 2024 08:28:06 -0800 Sean Christopherson seanjc@google.com wrote:
- /* Protection change for the range is going to happen. */
- if (p.arg.flags & PM_SCAN_WP_MATCHING) {
mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, 0,mm, p.arg.start, p.arg.end);mmu_notifier_invalidate_range_start(&range);- }
- for (walk_start = p.arg.start; walk_start < p.arg.end; walk_start = p.arg.walk_end) { long n_out;
Nit, might be worth moving
struct mmu_notifier_range range;inside the loop to guard against stale usage, but that's definitely optional.
Yes, I think that's nicer.
--- a/fs/proc/task_mmu.c~fs-proc-task_mmu-move-mmu-notification-mechanism-inside-mm-lock-fix +++ a/fs/proc/task_mmu.c @@ -2432,7 +2432,6 @@ static long pagemap_scan_flush_buffer(st
static long do_pagemap_scan(struct mm_struct *mm, unsigned long uarg) { - struct mmu_notifier_range range; struct pagemap_scan_private p = {0}; unsigned long walk_start; size_t n_ranges_out = 0; @@ -2450,6 +2449,7 @@ static long do_pagemap_scan(struct mm_st
for (walk_start = p.arg.start; walk_start < p.arg.end; walk_start = p.arg.walk_end) { + struct mmu_notifier_range range; long n_out;
if (fatal_signal_pending(current)) { _
I'm surprised this code doesn't generate a might-be-used-uninitialized warning. I guess gcc got smarter.