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SELinux fixups needed for preemptable RCU from -rt

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The attached patch needs to move from -rt to mainline given preemptable RCU.
This patch fixes SELinux code that implicitly assumes that disabling
preemption prevents an RCU grace period from completing, an assumption that
is valid for Classic RCU, but not necessarily for preemptable RCU.  Explicit
rcu_read_lock() calls are thus added.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Paul E. McKenney 2008-04-21 18:12:33 -07:00 committed by James Morris
parent 0f5e64200f
commit 6184425091
2 changed files with 11 additions and 0 deletions
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9
security/selinux/avc.c
View File

@ -312,6 +312,7 @@ static inline int avc_reclaim_node(void)
if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
continue;
rcu_read_lock();
list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
if (atomic_dec_and_test(&node->ae.used)) {
/* Recently Unused */
@ -319,11 +320,13 @@ static inline int avc_reclaim_node(void)
avc_cache_stats_incr(reclaims);
ecx++;
if (ecx >= AVC_CACHE_RECLAIM) {
rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
goto out;
}
}
}
rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
}
out:
@ -821,8 +824,14 @@ int avc_ss_reset(u32 seqno)
for (i = 0; i < AVC_CACHE_SLOTS; i++) {
spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
/*
* With preemptable RCU, the outer spinlock does not
* prevent RCU grace periods from ending.
*/
rcu_read_lock();
list_for_each_entry(node, &avc_cache.slots[i], list)
avc_node_delete(node);
rcu_read_unlock();
spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
}

2
security/selinux/netif.c
View File

@ -239,11 +239,13 @@ static void sel_netif_kill(int ifindex)
{
struct sel_netif *netif;
rcu_read_lock();
spin_lock_bh(&sel_netif_lock);
netif = sel_netif_find(ifindex);
if (netif)
sel_netif_destroy(netif);
spin_unlock_bh(&sel_netif_lock);
rcu_read_unlock();
}
/**