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ipv6: sr: fix several BUGs when preemption is enabled

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Lebrun 2017-01-12 21:30:01 +01:00 committed by David S. Miller
parent 148d3d021c
commit fa79581ea6
2 changed files with 5 additions and 1 deletions
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2
net/ipv6/seg6_hmac.c
View File

@ -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);

4
net/ipv6/seg6_iptunnel.c
View File

@ -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
}