3 files changed, 35 insertions, 32 deletions

diff --git a/usr/src/uts/common/os/brand.c b/usr/src/uts/common/os/brand.c
index 61aa562f73..00f2ce0440 100644
--- a/usr/src/uts/common/os/brand.c
+++ b/usr/src/uts/common/os/brand.c
@@ -1037,7 +1037,7 @@ brand_solaris_exec(struct brand *pbrand)
 
 	/* Upon exec, reset our lwp brand data. */
 	(void) brand_solaris_freelwp(ttolwp(curthread), pbrand);
-	(void) brand_solaris_brandlwp(ttolwp(curthread), pbrand);
+	(void) brand_solaris_initlwp(ttolwp(curthread), pbrand);
 
 	/*
 	 * Upon exec, reset all the proc brand data, except for the elf
@@ -1081,7 +1081,7 @@ brand_solaris_forklwp(klwp_t *p, klwp_t *c, struct brand *pbrand)
 
 	/*
 	 * Both LWPs have already had been initialized via
-	 * brand_solaris_brandlwp().
+	 * brand_solaris_initlwp().
 	 */
 	ASSERT(p->lwp_brand != NULL);
 	ASSERT(c->lwp_brand != NULL);
@@ -1098,14 +1098,13 @@ brand_solaris_freelwp(klwp_t *l, struct brand *pbrand)
 }
 
 /*ARGSUSED*/
-int
-brand_solaris_brandlwp(klwp_t *l, struct brand *pbrand)
+void
+brand_solaris_initlwp(klwp_t *l, struct brand *pbrand)
 {
 	ASSERT(l->lwp_procp->p_brand == pbrand);
 	ASSERT(l->lwp_procp->p_brand_data != NULL);
 	ASSERT(l->lwp_brand == NULL);
 	l->lwp_brand = (void *)-1;
-	return (0);
 }
 
 /*ARGSUSED*/
diff --git a/usr/src/uts/common/os/exec.c b/usr/src/uts/common/os/exec.c
index 4b6c79997e..7e32fb0506 100644
--- a/usr/src/uts/common/os/exec.c
+++ b/usr/src/uts/common/os/exec.c
@@ -301,19 +301,20 @@ exec_common(const char *fname, const char **argp, const char **envp,
 
 	/* If necessary, brand this process/lwp before we start the exec. */
 	if (brandme) {
+		void *brand_data = NULL;
+
 		brand_setbrand(p);
-		if (BROP(p)->b_brandlwp(lwp) != 0) {
+		if (BROP(p)->b_lwpdata_alloc != NULL &&
+		    (brand_data = BROP(p)->b_lwpdata_alloc(p)) == NULL) {
 			VN_RELE(vp);
 			if (dir != NULL)
 				VN_RELE(dir);
 			pn_free(&resolvepn);
 			goto fail;
 		}
-		if (BROP(p)->b_initlwp != NULL) {
-			mutex_enter(&p->p_lock);
-			BROP(p)->b_initlwp(lwp);
-			mutex_exit(&p->p_lock);
-		}
+		mutex_enter(&p->p_lock);
+		BROP(p)->b_initlwp(lwp, brand_data);
+		mutex_exit(&p->p_lock);
 	}
 
 	if ((error = gexec(&vp, &ua, &args, NULL, 0, &execsz,
diff --git a/usr/src/uts/common/os/lwp.c b/usr/src/uts/common/os/lwp.c
index 6b91e410d7..f5be1b40b3 100644
--- a/usr/src/uts/common/os/lwp.c
+++ b/usr/src/uts/common/os/lwp.c
@@ -115,7 +115,7 @@ lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p,
 	ret_tidhash_t *ret_tidhash = NULL;
 	int i;
 	int rctlfail = 0;
-	boolean_t branded = B_FALSE;
+	void *brand_data = NULL;
 	struct ctxop *ctx = NULL;
 
 	ASSERT(cid != sysdccid);	/* system threads must start in SYS */
@@ -283,6 +283,19 @@ lwp_create(void (*proc)(), caddr_t arg, size_t len, proc_t *p,
 	 */
 	lep = kmem_zalloc(sizeof (*lep), KM_SLEEP);
 
+	/*
+	 * If necessary, speculatively allocate lwp brand data.  This is done
+	 * ahead of time so p_lock need not be dropped during lwp branding.
+	 */
+	if (PROC_IS_BRANDED(p) && BROP(p)->b_lwpdata_alloc != NULL) {
+		if ((brand_data = BROP(p)->b_lwpdata_alloc(p)) == NULL) {
+			mutex_enter(&p->p_lock);
+			err = 1;
+			atomic_inc_32(&p->p_zone->zone_ffmisc);
+			goto error;
+		}
+	}
+
 	mutex_enter(&p->p_lock);
 grow:
 	/*
@@ -682,25 +695,15 @@ grow:
 	t->t_pre_sys = 1;
 	t->t_post_sys = 1;
 
-	mutex_exit(&p->p_lock);
-	/*
-	 * If this is a branded process, allocate any brand-specific lwp data.
-	 */
-	if (PROC_IS_BRANDED(p)) {
-		if (BROP(p)->b_brandlwp(lwp) != 0) {
-			mutex_enter(&p->p_lock);
-			err = 1;
-			atomic_inc_32(&p->p_zone->zone_ffmisc);
-			goto error;
-		}
-		branded = B_TRUE;
-	}
-
-	mutex_enter(&p->p_lock);
-
 	/* Complete branded lwp initialization */
-	if (branded && BROP(p)->b_initlwp != NULL) {
-		BROP(p)->b_initlwp(lwp);
+	if (PROC_IS_BRANDED(p)) {
+		BROP(p)->b_initlwp(lwp, brand_data);
+		/*
+		 * The b_initlwp hook is expected to consume any preallocated
+		 * brand_data in a way that prepares it for deallocation by the
+		 * b_freelwp hook.
+		 */
+		brand_data = NULL;
 	}
 
 	/*
@@ -762,8 +765,8 @@ error:
 		if (cid != NOCLASS && bufp != NULL)
 			CL_FREE(cid, bufp);
 
-		if (branded) {
-			BROP(p)->b_freelwp(lwp);
+		if (brand_data != NULL) {
+			BROP(p)->b_lwpdata_free(brand_data);
 		}
 
 		mutex_exit(&p->p_lock);