The patch titled
Subject: kernel/fork: detect mas_store() failure in dup_mmap()
has been added to the -mm mm-unstable branch. Its filename is
kernel-fork-use-maple-tree-for-dup_mmap-during-forking-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kernel-fork-use-maple-tree-for-dup_mmap-during-forking-fix.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Subject: kernel/fork: detect mas_store() failure in dup_mmap()
Date: Fri, 22 Jul 2022 16:06:03 +0000
mas_store() should not fail, but protect against potential failures by
checking the maple state for mas_is_err().
Link: https://lkml.kernel.org/r/20220722160546.1478722-3-Liam.Howlett@xxxxxxxxxx
Fixes: 57579b57de57 (kernel/fork: use maple tree for dup_mmap() during forking)
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/fork.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/kernel/fork.c~kernel-fork-use-maple-tree-for-dup_mmap-during-forking-fix
+++ a/kernel/fork.c
@@ -709,6 +709,8 @@ static __latent_entropy int dup_mmap(str
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))
@@ -732,6 +734,9 @@ out:
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:
_
Patches currently in -mm which might be from liam.howlett@xxxxxxxxxx are
android-binder-fix-lockdep-check-on-clearing-vma.patch
maple-tree-add-new-data-structure-fix.patch
kernel-fork-use-maple-tree-for-dup_mmap-during-forking-fix.patch
mm-mlock-drop-dead-code-in-count_mm_mlocked_page_nr.patch
