From 936e3a339b40ec2e8d0c2f59281e1c4b5e484f55 Mon Sep 17 00:00:00 2001
From: Gangadhar Mylapuram <Gangadhar.M@Sun.COM>
Date: Mon, 14 Sep 2009 23:58:59 -0700
Subject: 6814187 running newtask -c pid, could hang the system in pool code if
 the target process is in lwp_create

---
 usr/src/uts/common/os/lwp.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

(limited to 'usr/src/uts/common/os/lwp.c')

diff --git a/usr/src/uts/common/os/lwp.c b/usr/src/uts/common/os/lwp.c
index bf827dd106..45eaff29ef 100644
--- a/usr/src/uts/common/os/lwp.c
+++ b/usr/src/uts/common/os/lwp.c
@@ -58,6 +58,7 @@
 #include <sys/cmn_err.h>
 #include <sys/brand.h>
 #include <sys/cyclic.h>
+#include <sys/pool.h>
 
 /* hash function for the lwpid hash table, p->p_tidhash[] */
 #define	TIDHASH(tid, hash_sz)	((tid) & ((hash_sz) - 1))
@@ -394,8 +395,22 @@ grow:
 		 * We rely on stop() to call prbarrier(p) before returning.
 		 */
 		while ((curthread->t_proc_flag & TP_PRSTOP) &&
-		    !ttolwp(curthread)->lwp_nostop)
+		    !ttolwp(curthread)->lwp_nostop) {
+			/*
+			 * We called pool_barrier_enter() before calling
+			 * here to lwp_create(). We have to call
+			 * pool_barrier_exit() before stopping.
+			 */
+			pool_barrier_exit();
+			prbarrier(p);
 			stop(PR_REQUESTED, 0);
+			/*
+			 * And we have to repeat the call to
+			 * pool_barrier_enter after stopping.
+			 */
+			pool_barrier_enter();
+			prbarrier(p);
+		}
 
 		/*
 		 * If process is exiting, there could be a race between
-- 
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