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mmap: fix error paths with dup_anon_vma() 

commit 824135c46b upstream.

When the calling function fails after the dup_anon_vma(), the
duplication of the anon_vma is not being undone.  Add the necessary
unlink_anon_vma() call to the error paths that are missing them.

This issue showed up during inspection of the error path in vma_merge()
for an unrelated vma iterator issue.

Users may experience increased memory usage, which may be problematic as
the failure would likely be caused by a low memory situation.

Link: https://lkml.kernel.org/r/20230929183041.2835469-3-Liam.Howlett@oracle.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Liam R. Howlett 2023-09-29 14:30:40 -04:00 committed by Greg Kroah-Hartman
parent 21ca008c53
commit 9411dbe2c6
1 changed files with 14 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
mm/mmap.c
View File

@ -519,6 +519,7 @@ inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
struct anon_vma *anon_vma = vma->anon_vma;
struct file *file = vma->vm_file;
bool remove_next = false;
struct vm_area_struct *anon_dup = NULL;
if (next && (vma != next) && (end == next->vm_end)) {
remove_next = true;
@ -530,6 +531,8 @@ inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
error = anon_vma_clone(vma, next);
if (error)
return error;
anon_dup = vma;
}
}
@ -602,6 +605,9 @@ inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma,
return 0;
nomem:
if (anon_dup)
unlink_anon_vmas(anon_dup);
return -ENOMEM;
}
@ -629,6 +635,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
int remove_next = 0;
MA_STATE(mas, &mm->mm_mt, 0, 0);
struct vm_area_struct *exporter = NULL, *importer = NULL;
struct vm_area_struct *anon_dup = NULL;
if (next && !insert) {
if (end >= next->vm_end) {
@ -709,11 +716,17 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
error = anon_vma_clone(importer, exporter);
if (error)
return error;
anon_dup = importer;
}
}
if (mas_preallocate(&mas, vma, GFP_KERNEL))
if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
if (anon_dup)
unlink_anon_vmas(anon_dup);
return -ENOMEM;
}
vma_adjust_trans_huge(orig_vma, start, end, adjust_next);
if (file) {