* [PATCH] SELinux fixups needed for preemptable RCU from -rt
@ 2008-04-22 0:34 Paul E. McKenney
2008-04-22 0:54 ` Steven Rostedt
0 siblings, 1 reply; 5+ messages in thread
From: Paul E. McKenney @ 2008-04-22 0:34 UTC (permalink / raw)
To: linux-kernel; +Cc: mingo, akpm, rostedt, dwalker, sdietrich, dvhltc, niv
Hello!
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.
Pointed-out-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
security/selinux/avc.c | 9 +++++++++
security/selinux/netif.c | 2 ++
2 files changed, 11 insertions(+)
Index: linux-2.6.24.4-rt4/security/selinux/avc.c
===================================================================
--- linux-2.6.24.4-rt4.orig/security/selinux/avc.c 2008-03-24 19:05:09.000000000 -0400
+++ linux-2.6.24.4-rt4/security/selinux/avc.c 2008-03-24 19:06:41.000000000 -0400
@@ -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:
@@ -807,8 +810,14 @@ int avc_ss_reset(u32 seqno)
for (i = 0; i < AVC_CACHE_SLOTS; i++) {
spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
+ /*
+ * On -rt the outer spinlock does not prevent RCU
+ * from being performed:
+ */
+ 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);
}
Index: linux-2.6.24.4-rt4/security/selinux/netif.c
===================================================================
--- linux-2.6.24.4-rt4.orig/security/selinux/netif.c 2008-03-24 19:05:09.000000000 -0400
+++ linux-2.6.24.4-rt4/security/selinux/netif.c 2008-03-24 19:06:41.000000000 -0400
@@ -210,6 +210,7 @@ static void sel_netif_flush(void)
{
int idx;
+ rcu_read_lock();
spin_lock_bh(&sel_netif_lock);
for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
struct sel_netif *netif;
@@ -218,6 +219,7 @@ static void sel_netif_flush(void)
sel_netif_destroy(netif);
}
spin_unlock_bh(&sel_netif_lock);
+ rcu_read_unlock();
}
static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] SELinux fixups needed for preemptable RCU from -rt
2008-04-22 0:34 [PATCH] SELinux fixups needed for preemptable RCU from -rt Paul E. McKenney
@ 2008-04-22 0:54 ` Steven Rostedt
2008-04-22 1:12 ` Paul E. McKenney
0 siblings, 1 reply; 5+ messages in thread
From: Steven Rostedt @ 2008-04-22 0:54 UTC (permalink / raw)
To: Paul E. McKenney
Cc: linux-kernel, mingo, akpm, dwalker, sdietrich, dvhltc, niv
On Mon, 21 Apr 2008, Paul E. McKenney wrote:
> @@ -807,8 +810,14 @@ int avc_ss_reset(u32 seqno)
>
> for (i = 0; i < AVC_CACHE_SLOTS; i++) {
> spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
> + /*
> + * On -rt the outer spinlock does not prevent RCU
> + * from being performed:
I would suggest to change this comment to "With preemptible RCU" from
"On -rt".
-- Steve
> + */
> + 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);
> }
>
5A
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] SELinux fixups needed for preemptable RCU from -rt
2008-04-22 0:54 ` Steven Rostedt
@ 2008-04-22 1:12 ` Paul E. McKenney
2008-04-22 1:14 ` Steven Rostedt
2008-04-22 5:42 ` James Morris
0 siblings, 2 replies; 5+ messages in thread
From: Paul E. McKenney @ 2008-04-22 1:12 UTC (permalink / raw)
To: Steven Rostedt; +Cc: linux-kernel, mingo, akpm, dwalker, sdietrich, dvhltc, niv
On Mon, Apr 21, 2008 at 08:54:51PM -0400, Steven Rostedt wrote:
>
> On Mon, 21 Apr 2008, Paul E. McKenney wrote:
> > @@ -807,8 +810,14 @@ int avc_ss_reset(u32 seqno)
> >
> > for (i = 0; i < AVC_CACHE_SLOTS; i++) {
> > spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
> > + /*
> > + * On -rt the outer spinlock does not prevent RCU
> > + * from being performed:
>
> I would suggest to change this comment to "With preemptible RCU" from
> "On -rt".
Good point... How about the following?
> -- Steve
>
> > + */
> > + 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);
> > }
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> (comment change)
---
security/selinux/avc.c | 9 +++++++++
security/selinux/netif.c | 2 ++
2 files changed, 11 insertions(+)
Index: linux-2.6.24.4-rt4/security/selinux/avc.c
===================================================================
--- linux-2.6.24.4-rt4.orig/security/selinux/avc.c 2008-03-24 19:05:09.000000000 -0400
+++ linux-2.6.24.4-rt4/security/selinux/avc.c 2008-03-24 19:06:41.000000000 -0400
@@ -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:
@@ -807,8 +810,14 @@ 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);
}
Index: linux-2.6.24.4-rt4/security/selinux/netif.c
===================================================================
--- linux-2.6.24.4-rt4.orig/security/selinux/netif.c 2008-03-24 19:05:09.000000000 -0400
+++ linux-2.6.24.4-rt4/security/selinux/netif.c 2008-03-24 19:06:41.000000000 -0400
@@ -210,6 +210,7 @@ static void sel_netif_flush(void)
{
int idx;
+ rcu_read_lock();
spin_lock_bh(&sel_netif_lock);
for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
struct sel_netif *netif;
@@ -218,6 +219,7 @@ static void sel_netif_flush(void)
sel_netif_destroy(netif);
}
spin_unlock_bh(&sel_netif_lock);
+ rcu_read_unlock();
}
static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] SELinux fixups needed for preemptable RCU from -rt
2008-04-22 1:12 ` Paul E. McKenney
@ 2008-04-22 1:14 ` Steven Rostedt
2008-04-22 5:42 ` James Morris
1 sibling, 0 replies; 5+ messages in thread
From: Steven Rostedt @ 2008-04-22 1:14 UTC (permalink / raw)
To: Paul E. McKenney
Cc: linux-kernel, mingo, akpm, dwalker, sdietrich, dvhltc, niv
On Mon, 21 Apr 2008, Paul E. McKenney wrote:
> On Mon, Apr 21, 2008 at 08:54:51PM -0400, Steven Rostedt wrote:
> >
> > On Mon, 21 Apr 2008, Paul E. McKenney wrote:
> > > @@ -807,8 +810,14 @@ int avc_ss_reset(u32 seqno)
> > >
> > > for (i = 0; i < AVC_CACHE_SLOTS; i++) {
> > > spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
> > > + /*
> > > + * On -rt the outer spinlock does not prevent RCU
> > > + * from being performed:
> >
> > I would suggest to change this comment to "With preemptible RCU" from
> > "On -rt".
>
> Good point... How about the following?
Acked-by: Steven Rostedt <srostedt@redhat.com>
-- Steve
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] SELinux fixups needed for preemptable RCU from -rt
2008-04-22 1:12 ` Paul E. McKenney
2008-04-22 1:14 ` Steven Rostedt
@ 2008-04-22 5:42 ` James Morris
1 sibling, 0 replies; 5+ messages in thread
From: James Morris @ 2008-04-22 5:42 UTC (permalink / raw)
To: Paul E. McKenney
Cc: Steven Rostedt, linux-kernel, Ingo Molnar, Andrew Morton, dwalker,
sdietrich, dvhltc, niv, Eric Paris, Stephen Smalley
Thanks, applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/selinux-2.6.git#for-linus
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> (comment change)
> ---
> security/selinux/avc.c | 9 +++++++++
> security/selinux/netif.c | 2 ++
> 2 files changed, 11 insertions(+)
>
> Index: linux-2.6.24.4-rt4/security/selinux/avc.c
> ===================================================================
> --- linux-2.6.24.4-rt4.orig/security/selinux/avc.c 2008-03-24 19:05:09.000000000 -0400
> +++ linux-2.6.24.4-rt4/security/selinux/avc.c 2008-03-24 19:06:41.000000000 -0400
> @@ -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:
> @@ -807,8 +810,14 @@ 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);
> }
>
> Index: linux-2.6.24.4-rt4/security/selinux/netif.c
> ===================================================================
> --- linux-2.6.24.4-rt4.orig/security/selinux/netif.c 2008-03-24 19:05:09.000000000 -0400
> +++ linux-2.6.24.4-rt4/security/selinux/netif.c 2008-03-24 19:06:41.000000000 -0400
> @@ -210,6 +210,7 @@ static void sel_netif_flush(void)
> {
> int idx;
>
> + rcu_read_lock();
> spin_lock_bh(&sel_netif_lock);
> for (idx = 0; idx < SEL_NETIF_HASH_SIZE; idx++) {
> struct sel_netif *netif;
> @@ -218,6 +219,7 @@ static void sel_netif_flush(void)
> sel_netif_destroy(netif);
> }
> spin_unlock_bh(&sel_netif_lock);
> + rcu_read_unlock();
> }
>
> static int sel_netif_avc_callback(u32 event, u32 ssid, u32 tsid,
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
--
James Morris
<jmorris@namei.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-04-22 5:45 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-04-22 0:34 [PATCH] SELinux fixups needed for preemptable RCU from -rt Paul E. McKenney
2008-04-22 0:54 ` Steven Rostedt
2008-04-22 1:12 ` Paul E. McKenney
2008-04-22 1:14 ` Steven Rostedt
2008-04-22 5:42 ` James Morris
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.