diff options
| author | Pavel Emelyanov <xemul@openvz.org> | 2007-12-04 00:45:06 -0800 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-12-05 05:37:27 -0800 |
| commit | 4ac63ad6c52e9cdefbcb54ec4575ab12b78b49d9 (patch) | |
| tree | e8ff9d5a9bbe01c68a95f71f1707cc24afa770d1 /net | |
| parent | a014bc8f0f0a3a0cac4fef656f101cdfb77b71eb (diff) | |
[IPVS]: Fix sched registration race when checking for name collision.
The register_ip_vs_scheduler() checks for the scheduler with the
same name under the read-locked __ip_vs_sched_lock, then drops,
takes it for writing and puts the scheduler in list.
This is racy, since we can have a race window between the lock
being re-locked for writing.
The fix is to search the scheduler with the given name right under
the write-locked __ip_vs_sched_lock.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/ipvs/ip_vs_sched.c | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/net/ipv4/ipvs/ip_vs_sched.c b/net/ipv4/ipvs/ip_vs_sched.c index 1602304abbf..43223586190 100644 --- a/net/ipv4/ipvs/ip_vs_sched.c +++ b/net/ipv4/ipvs/ip_vs_sched.c @@ -183,19 +183,6 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) /* increase the module use count */ ip_vs_use_count_inc(); - /* - * Make sure that the scheduler with this name doesn't exist - * in the scheduler list. - */ - sched = ip_vs_sched_getbyname(scheduler->name); - if (sched) { - ip_vs_scheduler_put(sched); - ip_vs_use_count_dec(); - IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler " - "already existed in the system\n", scheduler->name); - return -EINVAL; - } - write_lock_bh(&__ip_vs_sched_lock); if (scheduler->n_list.next != &scheduler->n_list) { @@ -207,6 +194,20 @@ int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) } /* + * Make sure that the scheduler with this name doesn't exist + * in the scheduler list. + */ + list_for_each_entry(sched, &ip_vs_schedulers, n_list) { + if (strcmp(scheduler->name, sched->name) == 0) { + write_unlock_bh(&__ip_vs_sched_lock); + ip_vs_use_count_dec(); + IP_VS_ERR("register_ip_vs_scheduler(): [%s] scheduler " + "already existed in the system\n", + scheduler->name); + return -EINVAL; + } + } + /* * Add it into the d-linked scheduler list */ list_add(&scheduler->n_list, &ip_vs_schedulers); |