From: Shuangpeng Bai Date: Mon, 27 Jul 2026 18:53:39 +0000 (-0400) Subject: ipv6: release fib6_null_entry on subtree failure X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=93cad1f6bd1e27c75c4a5ab000c2a2fc01181ccf;p=thirdparty%2Fkernel%2Fstable.git ipv6: release fib6_null_entry on subtree failure When adding a source-specific route creates a new subtree, fib6_add() installs fib6_null_entry as the temporary leaf of the new subtree root and takes a fib6_info reference for that holder. If adding the first source leaf fails, the code frees the just allocated subtree root but leaves that hold behind. fib6_null_entry is a per-netns sentinel and is freed directly at netns teardown, so this does not keep the object alive. However, it leaves its visible refcount permanently elevated and can eventually saturate the refcount on repeated failures. Drop the null-entry reference before freeing the unlinked subtree root. Fixes: 5ea715289af6 ("ipv6: broadly use fib6_info_hold() helper") Signed-off-by: Shuangpeng Bai Reviewed-by: Ido Schimmel Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Link: https://patch.msgid.link/20260727185339.1545169-1-shuangpeng.kernel@gmail.com Signed-off-by: Jakub Kicinski --- diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index a130cdfaebfb..e9fc692d4f3b 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1494,6 +1494,7 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt, root, and then (in failure) stale node in main tree. */ + fib6_info_release(info->nl_net->ipv6.fib6_null_entry); node_free_immediate(info->nl_net, sfn); err = PTR_ERR(sn); goto failure;