From: Kent Overstreet kent.overstreet@linux.dev

stable inclusion from stable-v5.10.226 commit 99418ec776a39609f50934720419e0b464ca2283 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAVU82 CVE: CVE-2024-47668

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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[ Upstream commit b2f11c6f3e1fc60742673b8675c95b78447f3dae ]

If we need to increase the tree depth, allocate a new node, and then race with another thread that increased the tree depth before us, we'll still have a preallocated node that might be used later.

If we then use that node for a new non-root node, it'll still have a pointer to the old root instead of being zeroed - fix this by zeroing it in the cmpxchg failure path.

Signed-off-by: Kent Overstreet kent.overstreet@linux.dev Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zhang Zekun zhangzekun11@huawei.com --- lib/generic-radix-tree.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c index 7dfa88282b00..78f081d695d0 100644 --- a/lib/generic-radix-tree.c +++ b/lib/generic-radix-tree.c @@ -131,6 +131,8 @@ void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset, if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) { v = new_root; new_node = NULL; + } else { + new_node->children[0] = NULL; } }