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authorLiam R. Howlett <Liam.Howlett@oracle.com>2023-06-17 20:47:08 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-18 09:32:17 -0700
commit606c812eb1d5b5fb0dd9e330ca94b52d7c227830 (patch)
tree2458e45ab6a53c3d9b1424c9227fbf38898a6a23
parent1b29d271614abd97cc39782daa9d6dd70e98609f (diff)
mm/mmap: Fix error path in do_vmi_align_munmap()
The error unrolling was leaving the VMAs detached in many cases and leaving the locked_vm statistic altered, and skipping the unrolling entirely in the case of the vma tree write failing. Fix the error path by re-attaching the detached VMAs and adding the necessary goto for the failed vma tree write, and fix the locked_vm statistic by only updating after the vma tree write succeeds. Fixes: 763ecb035029 ("mm: remove the vma linked list") Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mmap.c37
1 files changed, 17 insertions, 20 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 13678edaa22c..d600404580b2 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2318,21 +2318,6 @@ int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
return __split_vma(vmi, vma, addr, new_below);
}
-static inline int munmap_sidetree(struct vm_area_struct *vma,
- struct ma_state *mas_detach)
-{
- vma_start_write(vma);
- mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1);
- if (mas_store_gfp(mas_detach, vma, GFP_KERNEL))
- return -ENOMEM;
-
- vma_mark_detached(vma, true);
- if (vma->vm_flags & VM_LOCKED)
- vma->vm_mm->locked_vm -= vma_pages(vma);
-
- return 0;
-}
-
/*
* do_vmi_align_munmap() - munmap the aligned region from @start to @end.
* @vmi: The vma iterator
@@ -2354,6 +2339,7 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
struct maple_tree mt_detach;
int count = 0;
int error = -ENOMEM;
+ unsigned long locked_vm = 0;
MA_STATE(mas_detach, &mt_detach, 0, 0);
mt_init_flags(&mt_detach, vmi->mas.tree->ma_flags & MT_FLAGS_LOCK_MASK);
mt_set_external_lock(&mt_detach, &mm->mmap_lock);
@@ -2399,9 +2385,13 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
if (error)
goto end_split_failed;
}
- error = munmap_sidetree(next, &mas_detach);
- if (error)
- goto munmap_sidetree_failed;
+ vma_start_write(next);
+ mas_set_range(&mas_detach, next->vm_start, next->vm_end - 1);
+ if (mas_store_gfp(&mas_detach, next, GFP_KERNEL))
+ goto munmap_gather_failed;
+ vma_mark_detached(next, true);
+ if (next->vm_flags & VM_LOCKED)
+ locked_vm += vma_pages(next);
count++;
#ifdef CONFIG_DEBUG_VM_MAPLE_TREE
@@ -2447,10 +2437,12 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
}
#endif
/* Point of no return */
+ error = -ENOMEM;
vma_iter_set(vmi, start);
if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL))
- return -ENOMEM;
+ goto clear_tree_failed;
+ mm->locked_vm -= locked_vm;
mm->map_count -= count;
/*
* Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or
@@ -2480,9 +2472,14 @@ do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma,
validate_mm(mm);
return downgrade ? 1 : 0;
+clear_tree_failed:
userfaultfd_error:
-munmap_sidetree_failed:
+munmap_gather_failed:
end_split_failed:
+ mas_set(&mas_detach, 0);
+ mas_for_each(&mas_detach, next, end)
+ vma_mark_detached(next, false);
+
__mt_destroy(&mt_detach);
start_split_failed:
map_count_exceeded: