Hello, On Mon, 15 Jan 2024, Fedor Pchelkin wrote: > Inside decrement_ttl() upon discovering that the packet ttl has exceeded, > __IP_INC_STATS and __IP6_INC_STATS macros can be called from preemptible > context having the following backtrace: > > check_preemption_disabled: 48 callbacks suppressed > BUG: using __this_cpu_add() in preemptible [00000000] code: curl/1177 > caller is decrement_ttl+0x217/0x830 > CPU: 5 PID: 1177 Comm: curl Not tainted 6.7.0+ #34 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 04/01/2014 > Call Trace: > <TASK> > dump_stack_lvl+0xbd/0xe0 > check_preemption_disabled+0xd1/0xe0 > decrement_ttl+0x217/0x830 > __ip_vs_get_out_rt+0x4e0/0x1ef0 > ip_vs_nat_xmit+0x205/0xcd0 > ip_vs_in_hook+0x9b1/0x26a0 > nf_hook_slow+0xc2/0x210 > nf_hook+0x1fb/0x770 > __ip_local_out+0x33b/0x640 > ip_local_out+0x2a/0x490 > __ip_queue_xmit+0x990/0x1d10 > __tcp_transmit_skb+0x288b/0x3d10 > tcp_connect+0x3466/0x5180 > tcp_v4_connect+0x1535/0x1bb0 > __inet_stream_connect+0x40d/0x1040 > inet_stream_connect+0x57/0xa0 > __sys_connect_file+0x162/0x1a0 > __sys_connect+0x137/0x160 > __x64_sys_connect+0x72/0xb0 > do_syscall_64+0x6f/0x140 > entry_SYSCALL_64_after_hwframe+0x6e/0x76 > RIP: 0033:0x7fe6dbbc34e0 > > Use the corresponding preemption-aware variants: IP_INC_STATS and > IP6_INC_STATS. > > Found by Linux Verification Center (linuxtesting.org). > > Fixes: 8d8e20e2d7bb ("ipvs: Decrement ttl") > Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx> Looks good to me, thanks! Acked-by: Julian Anastasov <ja@xxxxxx> > --- > net/netfilter/ipvs/ip_vs_xmit.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c > index 9193e109e6b3..65e0259178da 100644 > --- a/net/netfilter/ipvs/ip_vs_xmit.c > +++ b/net/netfilter/ipvs/ip_vs_xmit.c > @@ -271,7 +271,7 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs, > skb->dev = dst->dev; > icmpv6_send(skb, ICMPV6_TIME_EXCEED, > ICMPV6_EXC_HOPLIMIT, 0); > - __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); > + IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); > > return false; > } > @@ -286,7 +286,7 @@ static inline bool decrement_ttl(struct netns_ipvs *ipvs, > { > if (ip_hdr(skb)->ttl <= 1) { > /* Tell the sender its packet died... */ > - __IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); > + IP_INC_STATS(net, IPSTATS_MIB_INHDRERRORS); > icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0); > return false; > } > -- > 2.43.0 Regards -- Julian Anastasov <ja@xxxxxx>