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Subject[PATCH Fix 2/2] kernel/fork: Detect mas_store() failure in dup_mmap()
Date
mas_store() should not fail, but protect against potential failures by
checking the maple state for mas_is_err().

Fixes: 57579b57de57 (kernel/fork: use maple tree for dup_mmap() during forking)
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
kernel/fork.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/kernel/fork.c b/kernel/fork.c
index 2d7ce88da540..dfa2d5d22ed1 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -685,6 +685,8 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
mas.index = tmp->vm_start;
mas.last = tmp->vm_end - 1;
mas_store(&mas, tmp);
+ if (mas_is_err(&mas))
+ goto fail_nomem_mas_store;

mm->map_count++;
if (!(tmp->vm_flags & VM_WIPEONFORK))
@@ -708,6 +710,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
fail_uprobe_end:
uprobe_end_dup_mmap();
return retval;
+
+fail_nomem_mas_store:
+ unlink_anon_vmas(tmp);
fail_nomem_anon_vma_fork:
mpol_put(vma_policy(tmp));
fail_nomem_policy:
--
2.35.1
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