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| author | Kent Overstreet <kent.overstreet@linux.dev> | 2024-08-11 04:04:35 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-09-12 12:03:55 +0300 |
| commit | 0f27f4f445390cb7f73d4209cb2bf32834dc53da (patch) | |
| tree | 3dfb79a73af7c88e4afee9f4295128184b03ddd5 | |
| parent | defcaa426ba0bc89ffdafb799d2e50b52f74ffc4 (diff) | |
| download | linux-0f27f4f445390cb7f73d4209cb2bf32834dc53da.tar.xz | |
lib/generic-radix-tree.c: Fix rare race in __genradix_ptr_alloc()
[ 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>
| -rw-r--r-- | lib/generic-radix-tree.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/lib/generic-radix-tree.c b/lib/generic-radix-tree.c index f25eb111c051..34d3ac52de89 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; } } |