The quilt patch titled Subject: fs/proc/task_mmu: move mmu notification mechanism inside mm lock has been removed from the -mm tree. Its filename was fs-proc-task_mmu-move-mmu-notification-mechanism-inside-mm-lock.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Muhammad Usama Anjum usama.anjum@collabora.com Subject: fs/proc/task_mmu: move mmu notification mechanism inside mm lock Date: Tue, 9 Jan 2024 16:24:42 +0500

Move mmu notification mechanism inside mm lock to prevent race condition in other components which depend on it. The notifier will invalidate memory range. Depending upon the number of iterations, different memory ranges would be invalidated.

The following warning would be removed by this patch: WARNING: CPU: 0 PID: 5067 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:734 kvm_mmu_notifier_change_pte+0x860/0x960 arch/x86/kvm/../../../virt/kvm/kvm_main.c:734

There is no behavioural and performance change with this patch when there is no component registered with the mmu notifier.

[akpm@linux-foundation.org: narrow the scope of `range', per Sean] Link: https://lkml.kernel.org/r/20240109112445.590736-1-usama.anjum@collabora.com Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs") Signed-off-by: Muhammad Usama Anjum usama.anjum@collabora.com Reported-by: syzbot+81227d2bd69e9dedb802@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/000000000000f6d051060c6785bc@google.com/ Reviewed-by: Sean Christopherson seanjc@google.com Cc: Andrei Vagin avagin@google.com Cc: Arnd Bergmann arnd@arndb.de Cc: David Hildenbrand david@redhat.com Cc: Hugh Dickins hughd@google.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Liam R. Howlett Liam.Howlett@oracle.com Cc: Micha�� Miros��aw mirq-linux@rere.qmqm.pl Cc: Peter Xu peterx@redhat.com Cc: Ryan Roberts ryan.roberts@arm.com Cc: Stephen Rothwell sfr@canb.auug.org.au Cc: Suren Baghdasaryan surenb@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/proc/task_mmu.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-)

--- a/fs/proc/task_mmu.c~fs-proc-task_mmu-move-mmu-notification-mechanism-inside-mm-lock +++ 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; @@ -2448,15 +2447,9 @@ static long do_pagemap_scan(struct mm_st if (ret) return ret;

- /* 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) { + struct mmu_notifier_range range; long n_out;

if (fatal_signal_pending(current)) { @@ -2467,8 +2460,20 @@ static long do_pagemap_scan(struct mm_st ret = mmap_read_lock_killable(mm); if (ret) break; + + /* 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, walk_start, p.arg.end); + mmu_notifier_invalidate_range_start(&range); + } + ret = walk_page_range(mm, walk_start, p.arg.end, &pagemap_scan_ops, &p); + + if (p.arg.flags & PM_SCAN_WP_MATCHING) + mmu_notifier_invalidate_range_end(&range); + mmap_read_unlock(mm);

n_out = pagemap_scan_flush_buffer(&p); @@ -2494,9 +2499,6 @@ static long do_pagemap_scan(struct mm_st if (pagemap_scan_writeback_args(&p.arg, uarg)) ret = -EFAULT;

- if (p.arg.flags & PM_SCAN_WP_MATCHING) - mmu_notifier_invalidate_range_end(&range); - kfree(p.vec_buf); return ret; } _

Patches currently in -mm which might be from usama.anjum@collabora.com are

selftests-mm-mremap_test-fix-build-warning.patch selftests-mm-hugepage-shm-conform-test-to-tap-format-output.patch selftests-mm-hugepage-vmemmap-conform-test-to-tap-format-output.patch selftests-mm-hugetlb-madvise-conform-test-to-tap-format-output.patch selftests-mm-khugepaged-conform-test-to-tap-format-output.patch selftests-mm-hugetlb-read-hwpoison-conform-test-to-tap-format-output.patch selftests-mm-ksm_tests-conform-test-to-tap-format-output.patch selftests-mm-config-add-missing-configs.patch