From a35165ca101695aa2cc5a6300ef69ae60be39a49 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 22 Sep 2014 10:38:16 -0700 Subject: [PATCH] ipv4: do not use this_cpu_ptr() in preemptible context this_cpu_ptr() in preemptible context is generally bad Sep 22 05:05:55 br kernel: [ 94.608310] BUG: using smp_processor_id() in preemptible [00000000] code: ip/2261 Sep 22 05:05:55 br kernel: [ 94.608316] caller is tunnel_dst_set.isra.28+0x20/0x60 [ip_tunnel] Sep 22 05:05:55 br kernel: [ 94.608319] CPU: 3 PID: 2261 Comm: ip Not tainted 3.17.0-rc5 #82 We can simply use raw_cpu_ptr(), as preemption is safe in these contexts. Should fix https://bugzilla.kernel.org/show_bug.cgi?id=84991 Signed-off-by: Eric Dumazet Reported-by: Joe Fixes: 9a4aa9af447f ("ipv4: Use percpu Cache route in IP tunnels") Acked-by: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/ip_tunnel.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index afed1aac2638..bd41dd1948b6 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -79,10 +79,10 @@ static void __tunnel_dst_set(struct ip_tunnel_dst *idst, idst->saddr = saddr; } -static void tunnel_dst_set(struct ip_tunnel *t, +static noinline void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst, __be32 saddr) { - __tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst, saddr); + __tunnel_dst_set(raw_cpu_ptr(t->dst_cache), dst, saddr); } static void tunnel_dst_reset(struct ip_tunnel *t) @@ -106,7 +106,7 @@ static struct rtable *tunnel_rtable_get(struct ip_tunnel *t, struct dst_entry *dst; rcu_read_lock(); - idst = this_cpu_ptr(t->dst_cache); + idst = raw_cpu_ptr(t->dst_cache); dst = rcu_dereference(idst->dst); if (dst && !atomic_inc_not_zero(&dst->__refcnt)) dst = NULL; -- 2.20.1