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| author | Robert Shearman <rshearma@brocade.com> | 2017-01-24 16:26:48 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-04 09:47:11 +0100 |
| commit | e972cce0c833fa990622a2f46db79979ab07485c (patch) | |
| tree | 6f3d897e12aa1a9774185e17b328e298431aec63 /net | |
| parent | 89c2588627c20cf9d791a9bb1523646b101a59b1 (diff) | |
| download | linux-stable-e972cce0c833fa990622a2f46db79979ab07485c.tar.gz linux-stable-e972cce0c833fa990622a2f46db79979ab07485c.tar.bz2 linux-stable-e972cce0c833fa990622a2f46db79979ab07485c.zip | |
lwtunnel: Fix oops on state free after encap module unload
[ Upstream commit 85c814016ce3b371016c2c054a905fa2492f5a65 ]
When attempting to free lwtunnel state after the module for the encap
has been unloaded an oops occurs:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
IP: lwtstate_free+0x18/0x40
[..]
task: ffff88003e372380 task.stack: ffffc900001fc000
RIP: 0010:lwtstate_free+0x18/0x40
RSP: 0018:ffff88003fd83e88 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88002bbb3380 RCX: ffff88000c91a300
[..]
Call Trace:
<IRQ>
free_fib_info_rcu+0x195/0x1a0
? rt_fibinfo_free+0x50/0x50
rcu_process_callbacks+0x2d3/0x850
? rcu_process_callbacks+0x296/0x850
__do_softirq+0xe4/0x4cb
irq_exit+0xb0/0xc0
smp_apic_timer_interrupt+0x3d/0x50
apic_timer_interrupt+0x93/0xa0
[..]
Code: e8 6e c6 fc ff 89 d8 5b 5d c3 bb de ff ff ff eb f4 66 90 66 66 66 66 90 55 48 89 e5 53 0f b7 07 48 89 fb 48 8b 04 c5 00 81 d5 81 <48> 8b 40 08 48 85 c0 74 13 ff d0 48 8d 7b 20 be 20 00 00 00 e8
The problem is after the module for the encap can be unloaded the
corresponding ops is removed and is thus NULL here.
Modules implementing lwtunnel ops should not be allowed to unload
while there is state alive using those ops, so grab the module
reference for the ops on creating lwtunnel state and of course release
the reference when freeing the state.
Fixes: 1104d9ba443a ("lwtunnel: Add destroy state operation")
Signed-off-by: Robert Shearman <rshearma@brocade.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/lwtunnel.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c index 2f6db386624e..afa64f086d87 100644 --- a/net/core/lwtunnel.c +++ b/net/core/lwtunnel.c @@ -66,6 +66,15 @@ EXPORT_SYMBOL(lwtunnel_state_alloc); static const struct lwtunnel_encap_ops __rcu * lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly; +void lwtstate_free(struct lwtunnel_state *lws) +{ + const struct lwtunnel_encap_ops *ops = lwtun_encaps[lws->type]; + + kfree(lws); + module_put(ops->owner); +} +EXPORT_SYMBOL(lwtstate_free); + int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops, unsigned int num) { @@ -111,8 +120,11 @@ int lwtunnel_build_state(struct net_device *dev, u16 encap_type, ret = -EOPNOTSUPP; rcu_read_lock(); ops = rcu_dereference(lwtun_encaps[encap_type]); - if (likely(ops && ops->build_state)) + if (likely(ops && ops->build_state && try_module_get(ops->owner))) { ret = ops->build_state(dev, encap, family, cfg, lws); + if (ret) + module_put(ops->owner); + } rcu_read_unlock(); return ret; |