From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Set the start and end address for munmap when the prev and next are
gathered. This is needed to avoid incorrect addresses being used during
the vms_complete_munmap_vmas() function if the prev/next vma are
expanded.
Add a new helper vms_complete_pte_clear(), which is needed later and
will avoid growing the argument list to unmap_region() beyond the 9 it
already has.
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
---
mm/internal.h | 2 ++
mm/mmap.c | 37 ++++++++++++++++++++++++++++++-------
2 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/mm/internal.h b/mm/internal.h
index 02627e269d6b..ec8441362c28 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1493,6 +1493,8 @@ struct vma_munmap_struct {
struct list_head *uf; /* Userfaultfd list_head */
unsigned long start; /* Aligned start addr (inclusive) */
unsigned long end; /* Aligned end addr (exclusive) */
+ unsigned long unmap_start; /* Unmap PTE start */
+ unsigned long unmap_end; /* Unmap PTE end */
int vma_count; /* Number of vmas that will be removed */
unsigned long nr_pages; /* Number of pages being removed */
unsigned long locked_vm; /* Number of locked pages */
diff --git a/mm/mmap.c b/mm/mmap.c
index b940de8c6df8..7cc1f47122f6 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -530,6 +530,8 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms,
vms->vma_count = 0;
vms->nr_pages = vms->locked_vm = vms->nr_accounted = 0;
vms->exec_vm = vms->stack_vm = vms->data_vm = 0;
+ vms->unmap_start = FIRST_USER_ADDRESS;
+ vms->unmap_end = USER_PGTABLES_CEILING;
}
/*
@@ -2612,6 +2614,29 @@ static inline void abort_munmap_vmas(struct ma_state *mas_detach)
__mt_destroy(mas_detach->tree);
}
+
+static void vms_complete_pte_clear(struct vma_munmap_struct *vms,
+ struct ma_state *mas_detach, bool mm_wr_locked)
+{
+ struct mmu_gather tlb;
+
+ /*
+ * We can free page tables without write-locking mmap_lock because VMAs
+ * were isolated before we downgraded mmap_lock.
+ */
+ mas_set(mas_detach, 1);
+ lru_add_drain();
+ tlb_gather_mmu(&tlb, vms->mm);
+ update_hiwater_rss(vms->mm);
+ unmap_vmas(&tlb, mas_detach, vms->vma, vms->start, vms->end,
+ vms->vma_count, mm_wr_locked);
+ mas_set(mas_detach, 1);
+ /* start and end may be different if there is no prev or next vma. */
+ free_pgtables(&tlb, mas_detach, vms->vma, vms->unmap_start,
+ vms->unmap_end, mm_wr_locked);
+ tlb_finish_mmu(&tlb);
+}
+
/*
* vms_complete_munmap_vmas() - Finish the munmap() operation
* @vms: The vma munmap struct
@@ -2633,13 +2658,7 @@ static void vms_complete_munmap_vmas(struct vma_munmap_struct *vms,
if (vms->unlock)
mmap_write_downgrade(mm);
- /*
- * We can free page tables without write-locking mmap_lock because VMAs
- * were isolated before we downgraded mmap_lock.
- */
- mas_set(mas_detach, 1);
- unmap_region(mm, mas_detach, vms->vma, vms->prev, vms->next,
- vms->start, vms->end, vms->vma_count, !vms->unlock);
+ vms_complete_pte_clear(vms, mas_detach, !vms->unlock);
/* Update high watermark before we lower total_vm */
update_hiwater_vm(mm);
/* Stat accounting */
@@ -2701,6 +2720,8 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
goto start_split_failed;
}
vms->prev = vma_prev(vms->vmi);
+ if (vms->prev)
+ vms->unmap_start = vms->prev->vm_end;
/*
* Detach a range of VMAs from the mm. Using next as a temp variable as
@@ -2763,6 +2784,8 @@ static int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
}
vms->next = vma_next(vms->vmi);
+ if (vms->next)
+ vms->unmap_end = vms->next->vm_start;
#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
/* Make sure no VMAs are about to be lost. */
--
2.43.0
