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netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m 

When the netprio_cgroup module is not loaded, net_prio_subsys_id
is -1, and so sock_update_prioidx() accesses cgroup_subsys array
with negative index subsys[-1].

Make the code resembles cls_cgroup code, which is bug free.

Origionally-authored-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: "David S. Miller" <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Neil Horman 2012-02-10 05:43:38 +00:00 committed by David S. Miller
parent f5c38208d3
commit 2b73bc65e2
2 changed files with 42 additions and 13 deletions
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48
include/net/netprio_cgroup.h
View File

@ -37,19 +37,51 @@ extern int net_prio_subsys_id;
extern void sock_update_netprioidx(struct sock *sk);
static inline struct cgroup_netprio_state
*task_netprio_state(struct task_struct *p)
#if IS_BUILTIN(CONFIG_NETPRIO_CGROUP)
static inline u32 task_netprioidx(struct task_struct *p)
{
#if IS_ENABLED(CONFIG_NETPRIO_CGROUP)
return container_of(task_subsys_state(p, net_prio_subsys_id),
struct cgroup_netprio_state, css);
#else
return NULL;
#endif
struct cgroup_netprio_state *state;
u32 idx;
rcu_read_lock();
state = container_of(task_subsys_state(p, net_prio_subsys_id),
struct cgroup_netprio_state, css);
idx = state->prioidx;
rcu_read_unlock();
return idx;
}
#elif IS_MODULE(CONFIG_NETPRIO_CGROUP)
static inline u32 task_netprioidx(struct task_struct *p)
{
struct cgroup_netprio_state *state;
int subsys_id;
u32 idx = 0;
rcu_read_lock();
subsys_id = rcu_dereference_index_check(net_prio_subsys_id,
rcu_read_lock_held());
if (subsys_id >= 0) {
state = container_of(task_subsys_state(p, subsys_id),
struct cgroup_netprio_state, css);
idx = state->prioidx;
}
rcu_read_unlock();
return idx;
}
#else
static inline u32 task_netprioidx(struct task_struct *p)
{
return 0;
}
#endif /* CONFIG_NETPRIO_CGROUP */
#else
#define sock_update_netprioidx(sk)
#endif

7
net/core/sock.c
View File

@ -1171,13 +1171,10 @@ EXPORT_SYMBOL(sock_update_classid);
void sock_update_netprioidx(struct sock *sk)
{
struct cgroup_netprio_state *state;
if (in_interrupt())
return;
rcu_read_lock();
state = task_netprio_state(current);
sk->sk_cgrp_prioidx = state ? state->prioidx : 0;
rcu_read_unlock();
sk->sk_cgrp_prioidx = task_netprioidx(current);
}
EXPORT_SYMBOL_GPL(sock_update_netprioidx);
#endif