The patch titled
Subject: mm/vma: track start and end for munmap in vma_munmap_struct
has been added to the -mm mm-unstable branch. Its filename is
mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx>
Subject: mm/vma: track start and end for munmap in vma_munmap_struct
Date: Thu, 22 Aug 2024 15:25:34 -0400
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.
Link: https://lkml.kernel.org/r/20240822192543.3359552-13-Liam.Howlett@xxxxxxxxxx
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Bert Karwatzki <spasswolf@xxxxxx>
Cc: Jiri Olsa <olsajiri@xxxxxxxxx>
Cc: Kees Cook <kees@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vma.c | 32 +++++++++++++++++++++++++-------
mm/vma.h | 4 ++++
2 files changed, 29 insertions(+), 7 deletions(-)
--- a/mm/vma.c~mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct
+++ a/mm/vma.c
@@ -646,6 +646,26 @@ again:
uprobe_mmap(vp->insert);
}
+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
@@ -667,13 +687,7 @@ void vms_complete_munmap_vmas(struct vma
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 */
@@ -746,6 +760,8 @@ int vms_gather_munmap_vmas(struct vma_mu
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
@@ -810,6 +826,8 @@ int vms_gather_munmap_vmas(struct vma_mu
}
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. */
--- a/mm/vma.h~mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct
+++ a/mm/vma.h
@@ -38,6 +38,8 @@ 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 */
@@ -108,6 +110,8 @@ static inline void init_vma_munmap(struc
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;
}
int vms_gather_munmap_vmas(struct vma_munmap_struct *vms,
_
Patches currently in -mm which might be from Liam.Howlett@xxxxxxxxxx are
maple_tree-remove-rcu_read_lock-from-mt_validate.patch
mm-vma-correctly-position-vma_iterator-in-__split_vma.patch
mm-vma-introduce-abort_munmap_vmas.patch
mm-vma-introduce-vmi_complete_munmap_vmas.patch
mm-vma-extract-the-gathering-of-vmas-from-do_vmi_align_munmap.patch
mm-vma-introduce-vma_munmap_struct-for-use-in-munmap-operations.patch
mm-vma-change-munmap-to-use-vma_munmap_struct-for-accounting-and-surrounding-vmas.patch
mm-vma-change-munmap-to-use-vma_munmap_struct-for-accounting-and-surrounding-vmas-fix.patch
mm-vma-extract-validate_mm-from-vma_complete.patch
mm-vma-inline-munmap-operation-in-mmap_region.patch
mm-vma-expand-mmap_region-munmap-call.patch
mm-vma-support-vma-==-null-in-init_vma_munmap.patch
mm-mmap-reposition-vma-iterator-in-mmap_region.patch
mm-vma-track-start-and-end-for-munmap-in-vma_munmap_struct.patch
mm-clean-up-unmap_region-argument-list.patch
mm-mmap-avoid-zeroing-vma-tree-in-mmap_region.patch
mm-change-failure-of-map_fixed-to-restoring-the-gap-on-failure.patch
mm-mmap-use-phys_pfn-in-mmap_region.patch
mm-mmap-use-vms-accounted-pages-in-mmap_region.patch
ipc-shm-mm-drop-do_vma_munmap.patch
mm-move-may_expand_vm-check-in-mmap_region.patch
mm-vma-drop-incorrect-comment-from-vms_gather_munmap_vmas.patch
mm-vmah-optimise-vma_munmap_struct.patch
