[PATCH 0/3] Fixes for vma_merge() error path

[Liam R. Howlett]

Jann Horn reported a potential vma iterator issue in the failure path of
the vma_merge() code.  After examining the interface, it seemed the best
course of action is to simply add an undo path in the unlikely case of
an error.

On examining the vma iterator issue, another issue was discovered that
would increase the memory usage during failure scenarios, so this is
addressed in patch 2.

Since it is unclear in the code, another patch adds comments to the
vma_merge() function on why dup_anon_vma() is safe in 'case 6'.

Changes since v1:
 - Moved dup_anon_vma() call update from patch 1 to patch 2 - Thanks
   Matthew Wilcox
 - Changed comment on patch 1 - Thanks Andrew Morton

v1: https://lore.kernel.org/linux-mm/20230927160746.1928098-1-Liam.Howlett@xxxxxxxxxx/

Liam R. Howlett (3):
  mmap: Fix vma_iterator in error path of vma_merge()
  mmap: Fix error paths with dup_anon_vma()
  mmap: Add clarifying comment to vma_merge() code

 mm/mmap.c | 37 ++++++++++++++++++++++++++++---------
 1 file changed, 28 insertions(+), 9 deletions(-)

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2.40.1