diff options
| author | Liam R. Howlett <Liam.Howlett@oracle.com> | 2023-09-29 14:30:41 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-18 14:34:15 -0700 |
| commit | 9a12d103f7d2d524f5e3d4358b9a9c03e4a9f1d2 (patch) | |
| tree | 0bfee90c804169b6fb5078a4f6c20ba09931f105 /mm/mmap.c | |
| parent | 651acf0ceb72903ff16fe31e52c1c448a0ca880c (diff) | |
mmap: add clarifying comment to vma_merge() code
When tracing through the code in vma_merge(), it was not completely
clear why the error return to a dup_anon_vma() call would not overwrite
a previous attempt to the same function. This commit adds a comment
specifying why it is safe.
Link: https://lkml.kernel.org/r/20230929183041.2835469-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Jann Horn <jannh@google.com>
Link: https://lore.kernel.org/linux-mm/CAG48ez3iDwFPR=Ed1BfrNuyUJPMK_=StjxhUsCkL6po1s7bONg@mail.gmail.com/
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 011ba48d9e72..673429ee8a9e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -943,6 +943,11 @@ struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, vma_start_write(curr); remove = curr; remove2 = next; + /* + * Note that the dup_anon_vma below cannot overwrite err + * since the first caller would do nothing unless next + * has an anon_vma. + */ if (!next->anon_vma) err = dup_anon_vma(prev, curr, &anon_dup); } |