This is a note to let you know that I've just added the patch titled ipv4: use IS_ENABLED instead of ifdef to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ipv4-use-is_enabled-instead-of-ifdef.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From c09c8a27b9baa417864b9adc3228b10ae5eeec93 Mon Sep 17 00:00:00 2001 From: Florian Klink <flokli@xxxxxxxxx> Date: Sun, 15 Nov 2020 23:45:09 +0100 Subject: ipv4: use IS_ENABLED instead of ifdef From: Florian Klink <flokli@xxxxxxxxx> commit c09c8a27b9baa417864b9adc3228b10ae5eeec93 upstream. Checking for ifdef CONFIG_x fails if CONFIG_x=m. Use IS_ENABLED instead, which is true for both built-ins and modules. Otherwise, a > ip -4 route add 1.2.3.4/32 via inet6 fe80::2 dev eth1 fails with the message "Error: IPv6 support not enabled in kernel." if CONFIG_IPV6 is `m`. In the spirit of b8127113d01e53adba15b41aefd37b90ed83d631. Fixes: d15662682db2 ("ipv4: Allow ipv6 gateway with ipv4 routes") Cc: Kim Phillips <kim.phillips@xxxxxxx> Signed-off-by: Florian Klink <flokli@xxxxxxxxx> Reviewed-by: David Ahern <dsahern@xxxxxxxxxx> Link: https://lore.kernel.org/r/20201115224509.2020651-1-flokli@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/fib_frontend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -696,7 +696,7 @@ int fib_gw_from_via(struct fib_config *c cfg->fc_gw4 = *((__be32 *)via->rtvia_addr); break; case AF_INET6: -#ifdef CONFIG_IPV6 +#if IS_ENABLED(CONFIG_IPV6) if (alen != sizeof(struct in6_addr)) { NL_SET_ERR_MSG(extack, "Invalid IPv6 address in RTA_VIA"); return -EINVAL; Patches currently in stable-queue which might be from flokli@xxxxxxxxx are queue-5.9/ipv4-use-is_enabled-instead-of-ifdef.patch