| Message ID | 1484253001-29677-1-git-send-email-david.lebrun@uclouvain.be |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: David Lebrun <david.lebrun@uclouvain.be> Date: Thu, 12 Jan 2017 21:30:01 +0100 > When CONFIG_PREEMPT=y, CONFIG_IPV6=m and CONFIG_SEG6_HMAC=y, > seg6_hmac_init() is called during the initialization of the ipv6 module. > This causes a subsequent call to smp_processor_id() with preemption > enabled, resulting in the following trace. ... > Moreover, dst_cache_* functions also call smp_processor_id(), generating > a similar trace. > > This patch uses raw_cpu_ptr() in seg6_hmac_init() rather than this_cpu_ptr() > and disable preemption when using dst_cache_* functions. > > Signed-off-by: David Lebrun <david.lebrun@uclouvain.be> Applied, thanks.
diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c index ef1c8a4..03a0648 100644 --- a/net/ipv6/seg6_hmac.c +++ b/net/ipv6/seg6_hmac.c @@ -400,7 +400,7 @@ static int seg6_hmac_init_algo(void) *p_tfm = tfm; } - p_tfm = this_cpu_ptr(algo->tfms); + p_tfm = raw_cpu_ptr(algo->tfms); tfm = *p_tfm; shsize = sizeof(*shash) + crypto_shash_descsize(tfm); diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index bbfca22..1d60cb1 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -265,7 +265,9 @@ int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) slwt = seg6_lwt_lwtunnel(orig_dst->lwtstate); #ifdef CONFIG_DST_CACHE + preempt_disable(); dst = dst_cache_get(&slwt->cache); + preempt_enable(); #endif if (unlikely(!dst)) { @@ -286,7 +288,9 @@ int seg6_output(struct net *net, struct sock *sk, struct sk_buff *skb) } #ifdef CONFIG_DST_CACHE + preempt_disable(); dst_cache_set_ip6(&slwt->cache, dst, &fl6.saddr); + preempt_enable(); #endif }
When CONFIG_PREEMPT=y, CONFIG_IPV6=m and CONFIG_SEG6_HMAC=y, seg6_hmac_init() is called during the initialization of the ipv6 module. This causes a subsequent call to smp_processor_id() with preemption enabled, resulting in the following trace. [ 20.451460] BUG: using smp_processor_id() in preemptible [00000000] code: systemd/1 [ 20.452556] caller is debug_smp_processor_id+0x17/0x19 [ 20.453304] CPU: 0 PID: 1 Comm: systemd Not tainted 4.9.0-rc5-00973-g46738b1 #1 [ 20.454406] ffffc9000062fc18 ffffffff813607b2 0000000000000000 ffffffff81a7f782 [ 20.455528] ffffc9000062fc48 ffffffff813778dc 0000000000000000 00000000001dcf98 [ 20.456539] ffffffffa003bd08 ffffffff81af93e0 ffffc9000062fc58 ffffffff81377905 [ 20.456539] Call Trace: [ 20.456539] [<ffffffff813607b2>] dump_stack+0x63/0x7f [ 20.456539] [<ffffffff813778dc>] check_preemption_disabled+0xd1/0xe3 [ 20.456539] [<ffffffff81377905>] debug_smp_processor_id+0x17/0x19 [ 20.460260] [<ffffffffa0061f3b>] seg6_hmac_init+0xfa/0x192 [ipv6] [ 20.460260] [<ffffffffa0061ccc>] seg6_init+0x39/0x6f [ipv6] [ 20.460260] [<ffffffffa006121a>] inet6_init+0x21a/0x321 [ipv6] [ 20.460260] [<ffffffffa0061000>] ? 0xffffffffa0061000 [ 20.460260] [<ffffffff81000457>] do_one_initcall+0x8b/0x115 [ 20.460260] [<ffffffff811328a3>] do_init_module+0x53/0x1c4 [ 20.460260] [<ffffffff8110650a>] load_module+0x1153/0x14ec [ 20.460260] [<ffffffff81106a7b>] SYSC_finit_module+0x8c/0xb9 [ 20.460260] [<ffffffff81106a7b>] ? SYSC_finit_module+0x8c/0xb9 [ 20.460260] [<ffffffff81106abc>] SyS_finit_module+0x9/0xb [ 20.460260] [<ffffffff810014d1>] do_syscall_64+0x62/0x75 [ 20.460260] [<ffffffff816834f0>] entry_SYSCALL64_slow_path+0x25/0x25 Moreover, dst_cache_* functions also call smp_processor_id(), generating a similar trace. This patch uses raw_cpu_ptr() in seg6_hmac_init() rather than this_cpu_ptr() and disable preemption when using dst_cache_* functions. Signed-off-by: David Lebrun <david.lebrun@uclouvain.be> --- net/ipv6/seg6_hmac.c | 2 +- net/ipv6/seg6_iptunnel.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-)