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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2012-01-26 04:41:38 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2012-01-26 22:36:19 +0400 |
| commit | 073862ba5d249c20bd5c49fc6d904ff0e1f6a672 (patch) | |
| tree | e2bfd8ac4565532845a7213ce33ee7abae65530a /net/core | |
| parent | fddb7b5761f104f034a0e708ece756d9b2eb2cac (diff) | |
| download | linux-073862ba5d249c20bd5c49fc6d904ff0e1f6a672.tar.xz | |
netns: fix net_alloc_generic()
When a new net namespace is created, we should attach to it a "struct
net_generic" with enough slots (even empty), or we can hit the following
BUG_ON() :
[ 200.752016] kernel BUG at include/net/netns/generic.h:40!
...
[ 200.752016] [<ffffffff825c3cea>] ? get_cfcnfg+0x3a/0x180
[ 200.752016] [<ffffffff821cf0b0>] ? lockdep_rtnl_is_held+0x10/0x20
[ 200.752016] [<ffffffff825c41be>] caif_device_notify+0x2e/0x530
[ 200.752016] [<ffffffff810d61b7>] notifier_call_chain+0x67/0x110
[ 200.752016] [<ffffffff810d67c1>] raw_notifier_call_chain+0x11/0x20
[ 200.752016] [<ffffffff821bae82>] call_netdevice_notifiers+0x32/0x60
[ 200.752016] [<ffffffff821c2b26>] register_netdevice+0x196/0x300
[ 200.752016] [<ffffffff821c2ca9>] register_netdev+0x19/0x30
[ 200.752016] [<ffffffff81c1c67a>] loopback_net_init+0x4a/0xa0
[ 200.752016] [<ffffffff821b5e62>] ops_init+0x42/0x180
[ 200.752016] [<ffffffff821b600b>] setup_net+0x6b/0x100
[ 200.752016] [<ffffffff821b6466>] copy_net_ns+0x86/0x110
[ 200.752016] [<ffffffff810d5789>] create_new_namespaces+0xd9/0x190
net_alloc_generic() should take into account the maximum index into the
ptr array, as a subsystem might use net_generic() anytime.
This also reduces number of reallocations in net_assign_generic()
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Tested-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sjur Brændeland <sjur.brandeland@stericsson.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/net_namespace.c | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index aefcd7acbffa..0e950fda9a0a 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -30,6 +30,20 @@ EXPORT_SYMBOL(init_net); #define INITIAL_NET_GEN_PTRS 13 /* +1 for len +2 for rcu_head */ +static unsigned int max_gen_ptrs = INITIAL_NET_GEN_PTRS; + +static struct net_generic *net_alloc_generic(void) +{ + struct net_generic *ng; + size_t generic_size = offsetof(struct net_generic, ptr[max_gen_ptrs]); + + ng = kzalloc(generic_size, GFP_KERNEL); + if (ng) + ng->len = max_gen_ptrs; + + return ng; +} + static int net_assign_generic(struct net *net, int id, void *data) { struct net_generic *ng, *old_ng; @@ -43,8 +57,7 @@ static int net_assign_generic(struct net *net, int id, void *data) if (old_ng->len >= id) goto assign; - ng = kzalloc(sizeof(struct net_generic) + - id * sizeof(void *), GFP_KERNEL); + ng = net_alloc_generic(); if (ng == NULL) return -ENOMEM; @@ -59,7 +72,6 @@ static int net_assign_generic(struct net *net, int id, void *data) * the old copy for kfree after a grace period. */ - ng->len = id; memcpy(&ng->ptr, &old_ng->ptr, old_ng->len * sizeof(void*)); rcu_assign_pointer(net->gen, ng); @@ -161,18 +173,6 @@ out_undo: goto out; } -static struct net_generic *net_alloc_generic(void) -{ - struct net_generic *ng; - size_t generic_size = sizeof(struct net_generic) + - INITIAL_NET_GEN_PTRS * sizeof(void *); - - ng = kzalloc(generic_size, GFP_KERNEL); - if (ng) - ng->len = INITIAL_NET_GEN_PTRS; - - return ng; -} #ifdef CONFIG_NET_NS static struct kmem_cache *net_cachep; @@ -483,6 +483,7 @@ again: } return error; } + max_gen_ptrs = max_t(unsigned int, max_gen_ptrs, *ops->id); } error = __register_pernet_operations(list, ops); if (error) { |