Hello, On Sat, 14 Dec 2024, David Laight wrote: > 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. 8 ? > > 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 <lkft@xxxxxxxxxx> > Closes: https://lore.kernel.org/all/CA+G9fYsT34UkGFKxus63H6UVpYi5GRZkezT9MRLfAbM3f6ke0g@xxxxxxxxxxxxxx/ > Fixes: 4f325e26277b ("ipvs: dynamically limit the connection hash table") > Tested-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> > Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx> > Signed-off-by: David Laight <david.laight@xxxxxxxxxx> Looks good to me, thanks to everyone! Acked-by: Julian Anastasov <ja@xxxxxx> Pablo, Simon, probably, this should be applied to the 'nf' tree as it fixes a build failure... > --- > > Julian seems to be waiting for a 'v2' from me. > Changed target tree to 'net-next'. > I've re-written the commit message. > Copied Andrew Morton - he might want to take the change through the 'mm' tree. > Plausibly the 'fixes' tag should refer to the minmax.h change? > This will need back-porting if the minmax set get back-ported. > > I'm not sure whether there ought to be an attribution to Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > 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 98d7dbe3d787..c0289f83f96d 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; > > -- > 2.17.1 Regards -- Julian Anastasov <ja@xxxxxx>
