From: Filipe Manana Date: Wed, 16 Apr 2025 15:00:28 +0000 (+0100) Subject: btrfs: exit after state split error at set_extent_bit() X-Git-Tag: v6.16-rc1~214^2~62 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=41d69d4d78d8b179bf3bcdfc56d28a12b3a608d2;p=thirdparty%2Flinux.git btrfs: exit after state split error at set_extent_bit() If split_state() returned an error we call extent_io_tree_panic() which will trigger a BUG() call. However if CONFIG_BUG is disabled, which is an uncommon and exotic scenario, then we fallthrough and hit a use after free when calling set_state_bits() since the extent state record which the local variable 'prealloc' points to was freed by split_state(). So jump to the label 'out' after calling extent_io_tree_panic() and set the 'prealloc' pointer to NULL since split_state() has already freed it when it hit an error. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c index 29cf3a01294f6..36bdf9df7b4ca 100644 --- a/fs/btrfs/extent-io-tree.c +++ b/fs/btrfs/extent-io-tree.c @@ -1250,8 +1250,11 @@ hit_next: if (!prealloc) goto search_again; ret = split_state(tree, state, prealloc, end + 1); - if (ret) + if (ret) { extent_io_tree_panic(tree, state, "split", ret); + prealloc = NULL; + goto out; + } set_state_bits(tree, prealloc, bits, changeset); cache_state(prealloc, cached_state);