5.4-stable review patch. If anyone has any objections, please let me know.
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From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit d6938c1c76c64f42363d0d1f051e1b4641c2ad40 ]
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@ispras.ru Acked-by: Julian Anastasov ja@ssi.bg Acked-by: Simon Horman horms@kernel.org Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 43ef3e25ea7d..5c81772158d8 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; }