[Xen-changelog] [xen-3.4-testing] xsm/flask: Fix sidtab locking bug

["Xen patchbot-3.4-testing" <patchbot-3.4-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1250696129 -3600
# Node ID 5eb1cb326a25f637070ffca052938a2911910b2c
# Parent  35c0b153982f4355ab9cfa5467f286900ebb16e8
xsm/flask:  Fix sidtab locking bug

We do not need to use the _irqsave/irqrestore forms of spin locking
within the sidtab in Xen's XSM Flask module, and doing so triggers a
BUG_ON() within check_lock() when we subsequently call xmalloc().
This was preventing Xen from booting with XSM/Flask enabled if built
with debug=y. It appears that this broke upon the changes to xmalloc
in changeset 18379:14a9a1629590.

Signed-off-by: Stephen D. Smalley <sds@xxxxxxxxxxxxx>
Signed-off-by: George S. Coker, II <gscoker@xxxxxxxxxxxxxx>
xen-unstable changeset:   20063:ef3209bb5063
xen-unstable date:        Fri Aug 14 17:08:12 2009 +0100
---
 xen/xsm/flask/ss/sidtab.c |   23 +++++++++--------------
 1 files changed, 9 insertions(+), 14 deletions(-)

diff -r 35c0b153982f -r 5eb1cb326a25 xen/xsm/flask/ss/sidtab.c
--- a/xen/xsm/flask/ss/sidtab.c Wed Aug 19 16:34:58 2009 +0100
+++ b/xen/xsm/flask/ss/sidtab.c Wed Aug 19 16:35:29 2009 +0100
@@ -17,8 +17,8 @@
 #define SIDTAB_HASH(sid) (sid & SIDTAB_HASH_MASK)
 
 #define INIT_SIDTAB_LOCK(s) spin_lock_init(&s->lock)
-#define SIDTAB_LOCK(s, x) spin_lock_irqsave(&s->lock, x)
-#define SIDTAB_UNLOCK(s, x) spin_unlock_irqrestore(&s->lock, x)
+#define SIDTAB_LOCK(s) spin_lock(&s->lock)
+#define SIDTAB_UNLOCK(s) spin_unlock(&s->lock)
 
 int sidtab_init(struct sidtab *s)
 {
@@ -216,14 +216,13 @@ int sidtab_context_to_sid(struct sidtab 
 {
     u32 sid;
     int ret = 0;
-    unsigned long flags;
 
     *out_sid = SECSID_NULL;
 
     sid = sidtab_search_context(s, context);
     if ( !sid )
     {
-        SIDTAB_LOCK(s, flags);
+        SIDTAB_LOCK(s);
         /* Rescan now that we hold the lock. */
         sid = sidtab_search_context(s, context);
         if ( sid )
@@ -239,7 +238,7 @@ int sidtab_context_to_sid(struct sidtab 
         if ( ret )
             s->next_sid--;
 unlock_out:
-        SIDTAB_UNLOCK(s, flags);
+        SIDTAB_UNLOCK(s);
     }
 
     if ( ret )
@@ -307,21 +306,17 @@ void sidtab_destroy(struct sidtab *s)
 
 void sidtab_set(struct sidtab *dst, struct sidtab *src)
 {
-    unsigned long flags;
-
-    SIDTAB_LOCK(src, flags);
+    SIDTAB_LOCK(src);
     dst->htable = src->htable;
     dst->nel = src->nel;
     dst->next_sid = src->next_sid;
     dst->shutdown = 0;
-    SIDTAB_UNLOCK(src, flags);
+    SIDTAB_UNLOCK(src);
 }
 
 void sidtab_shutdown(struct sidtab *s)
 {
-    unsigned long flags;
-
-    SIDTAB_LOCK(s, flags);
+    SIDTAB_LOCK(s);
     s->shutdown = 1;
-    SIDTAB_UNLOCK(s, flags);
-}
+    SIDTAB_UNLOCK(s);
+}

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