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Mindaugas R. wrote:

> Memory allocation/freeing and other operations which may block should
> not be performed with the lock held.

Right. I reorganized the code to take care of all the places where it
would allocate/free memory with p_smutex held -- please take a look to
see if I forgot something.

That said, the call to the kauth authorization wrapper is still done
with p_smutex held. For example in sys__sched_setparam(), the logic is

	p = p_find(pid, PFIND_UNLOCK_FAIL);
	mutex_enter(&p->p_smutex);
	mutex_exit(&proclist_lock);

so I don't see how we can call kauth with p without having either
proclist_list or p_smutex held.

-e.

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Index: sys_sched.c
===================================================================
RCS file: /cvsroot/src/sys/kern/sys_sched.c,v
retrieving revision 1.9
diff -u -p -r1.9 sys_sched.c
--- sys_sched.c	31 Jan 2008 01:21:17 -0000	1.9
+++ sys_sched.c	1 Feb 2008 13:57:50 -0000
@@ -117,11 +117,6 @@ sys__sched_setparam(struct lwp *l, const
 	pri_t pri;
 	int error;
 
-	/* Available only for super-user */
-	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
-	    KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_SETPARAM), NULL, NULL, NULL))
-		return EPERM;
-
 	/* Get the parameters from the user-space */
 	sp = kmem_zalloc(sizeof(struct sched_param), KM_SLEEP);
 	error = copyin(SCARG(uap, params), sp, sizeof(struct sched_param));
@@ -163,6 +158,13 @@ sys__sched_setparam(struct lwp *l, const
 		mutex_enter(&p->p_smutex);
 	}
 
+	/* Available only for super-user */
+	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER, p,
+	    KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_SETPARAM), NULL, NULL)) {
+		mutex_exit(&p->p_smutex);
+		return EPERM;
+	}
+
 	/* Find the LWP(s) */
 	lcnt = 0;
 	lid = SCARG(uap, lid);
@@ -212,12 +214,6 @@ sys__sched_getparam(struct lwp *l, const
 	lwpid_t lid;
 	int error;
 
-	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
-	    KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_GETPARAM), NULL, NULL, NULL))
-		return EPERM;
-
-	sp = kmem_zalloc(sizeof(struct sched_param), KM_SLEEP);
-
 	/* If not specified, use the first LWP */
 	lid = SCARG(uap, lid) == 0 ? 1 : SCARG(uap, lid);
 
@@ -234,9 +230,16 @@ sys__sched_getparam(struct lwp *l, const
 		mutex_exit(&p->p_smutex);
 	}
 	if (t == NULL) {
-		kmem_free(sp, sizeof(struct sched_param));
 		return ESRCH;
 	}
+
+	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
+	    t->l_proc, KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_GETPARAM), NULL,
+	    NULL))
+		return EPERM;
+
+	sp = kmem_zalloc(sizeof(struct sched_param), KM_SLEEP);
+
 	sp->sched_priority = t->l_priority;
 	sp->sched_class = t->l_class;
 	lwp_unlock(t);
@@ -268,7 +271,7 @@ sys__sched_setaffinity(struct lwp *l,
 		syscallarg(size_t) size;
 		syscallarg(void *) cpuset;
 	} */
-	cpuset_t *cpuset;
+	cpuset_t *cpuset = NULL;
 	struct cpu_info *ci = NULL;
 	struct proc *p;
 	struct lwp *t;
@@ -277,12 +280,6 @@ sys__sched_setaffinity(struct lwp *l,
 	u_int lcnt;
 	int error;
 
-	/* Available only for super-user */
-	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
-	    l->l_proc, KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_SETAFFINITY), NULL,
-	    NULL))
-		return EPERM;
-
 	if (SCARG(uap, size) <= 0)
 		return EINVAL;
 
@@ -290,17 +287,8 @@ sys__sched_setaffinity(struct lwp *l,
 	cpuset = kmem_zalloc(sizeof(cpuset_t), KM_SLEEP);
 	error = copyin(SCARG(uap, cpuset), cpuset,
 	    min(SCARG(uap, size), sizeof(cpuset_t)));
-	if (error)
+	if (error) {
 		goto error;
-
-	/* Look for a CPU in the set */
-	for (CPU_INFO_FOREACH(cii, ci))
-		if (CPU_ISSET(cpu_index(ci), cpuset))
-			break;
-	if (ci == NULL) {
-		/* Empty set */
-		kmem_free(cpuset, sizeof(cpuset_t));
-		cpuset = NULL; 
 	}
 
 	if (SCARG(uap, pid) != 0) {
@@ -325,6 +313,25 @@ sys__sched_setaffinity(struct lwp *l,
 		goto error;
 	}
 
+	/* Available only for super-user */
+	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER, p,
+	    KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_SETAFFINITY), NULL,
+	    NULL)) {
+		mutex_exit(&p->p_smutex);
+		error = EPERM;
+		goto error;
+	}
+
+	/* Look for a CPU in the set */
+	for (CPU_INFO_FOREACH(cii, ci))
+		if (CPU_ISSET(cpu_index(ci), cpuset))
+			break;
+	if (ci == NULL) {
+		/* Empty set */
+		kmem_free(cpuset, sizeof(cpuset_t));
+		cpuset = NULL; 
+	}
+
 	/* Find the LWP(s) */
 	lcnt = 0;
 	lid = SCARG(uap, lid);
@@ -375,13 +382,6 @@ sys__sched_getaffinity(struct lwp *l,
 	if (SCARG(uap, size) <= 0)
 		return EINVAL;
 
-	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
-	    l->l_proc, KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_GETAFFINITY), NULL,
-	    NULL))
-		return EPERM;
-
-	cpuset = kmem_zalloc(sizeof(cpuset_t), KM_SLEEP);
-
 	/* If not specified, use the first LWP */
 	lid = SCARG(uap, lid) == 0 ? 1 : SCARG(uap, lid);
 
@@ -398,9 +398,16 @@ sys__sched_getaffinity(struct lwp *l,
 		mutex_exit(&p->p_smutex);
 	}
 	if (t == NULL) {
-		kmem_free(cpuset, sizeof(cpuset_t));
 		return ESRCH;
 	}
+
+	if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_SCHEDULER,
+	    t->l_proc, KAUTH_ARG(KAUTH_REQ_PROCESS_SCHEDULER_GETAFFINITY), NULL,
+	    NULL))
+		return EPERM;
+
+	cpuset = kmem_zalloc(sizeof(cpuset_t), KM_SLEEP);
+
 	if (t->l_flag & LW_AFFINITY)
 		memcpy(cpuset, &t->l_affinity, sizeof(cpuset_t));
 	lwp_unlock(t);

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