From 9c2569d2dc5cde0cca4ae1d67f2ddae35f983ae4 Mon Sep 17 00:00:00 2001 From: David Laight Date: Fri, 14 Mar 2025 12:03:09 +0900 Subject: [PATCH] ipvs: Fix clamp() of ip_vs_conn_tab on small memory systems BugLink: https://bugs.launchpad.net/bugs/2102266 [ Upstream commit cf2c97423a4f89c8b798294d3f34ecfe7e7035c3 ] The 'max_avail' value is calculated from the system memory size using order_base_2(). order_base_2(x) is defined as '(x) ? fn(x) : 0'. The compiler generates two copies of the code that follows and then expands clamp(max, min, PAGE_SHIFT - 12) (11 on 32bit). This triggers a compile-time assert since min is 5. In reality a system would have to have less than 512MB memory for the bounds passed to clamp to be reversed. Swap the order of the arguments to clamp() to avoid the warning. Replace the clamp_val() on the line below with clamp(). clamp_val() is just 'an accident waiting to happen' and not needed here. Detected by compile time checks added to clamp(), specifically: minmax.h: use BUILD_BUG_ON_MSG() for the lo < hi test in clamp() Reported-by: Linux Kernel Functional Testing Closes: https://lore.kernel.org/all/CA+G9fYsT34UkGFKxus63H6UVpYi5GRZkezT9MRLfAbM3f6ke0g@mail.gmail.com/ Fixes: 4f325e26277b ("ipvs: dynamically limit the connection hash table") Tested-by: Bartosz Golaszewski Reviewed-by: Bartosz Golaszewski Signed-off-by: David Laight Acked-by: Julian Anastasov Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Mehmet Basaran --- net/netfilter/ipvs/ip_vs_conn.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/ipvs/ip_vs_conn.c b/net/netfilter/ipvs/ip_vs_conn.c index a743db073887..98759ed1d3dd 100644 --- a/net/netfilter/ipvs/ip_vs_conn.c +++ b/net/netfilter/ipvs/ip_vs_conn.c @@ -1495,8 +1495,8 @@ int __init ip_vs_conn_init(void) max_avail -= 2; /* ~4 in hash row */ max_avail -= 1; /* IPVS up to 1/2 of mem */ max_avail -= order_base_2(sizeof(struct ip_vs_conn)); - max = clamp(max, min, max_avail); - ip_vs_conn_tab_bits = clamp_val(ip_vs_conn_tab_bits, min, max); + max = clamp(max_avail, min, max); + ip_vs_conn_tab_bits = clamp(ip_vs_conn_tab_bits, min, max); ip_vs_conn_tab_size = 1 << ip_vs_conn_tab_bits; ip_vs_conn_tab_mask = ip_vs_conn_tab_size - 1;