From owner-freebsd-threads@FreeBSD.ORG Sun Apr 27 04:40:04 2008 Return-Path: Delivered-To: freebsd-threads@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 44AAF106567C for ; Sun, 27 Apr 2008 04:40:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 33DA08FC0C for ; Sun, 27 Apr 2008 04:40:04 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.2/8.14.2) with ESMTP id m3R4e4qq063505 for ; Sun, 27 Apr 2008 04:40:04 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.2/8.14.1/Submit) id m3R4e4Cr063504; Sun, 27 Apr 2008 04:40:04 GMT (envelope-from gnats) Date: Sun, 27 Apr 2008 04:40:04 GMT Message-Id: <200804270440.m3R4e4Cr063504@freefall.freebsd.org> To: freebsd-threads@FreeBSD.org From: Andy Newman Cc: Subject: Re: threads/123062: C++ exception handling can loop during stacking unwinding in multithreaded programs X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Andy Newman List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 27 Apr 2008 04:40:04 -0000 The following reply was made to PR threads/123062; it has been noted by GNATS. From: Andy Newman To: bug-followup@FreeBSD.org, Andy Newman Cc: Subject: Re: threads/123062: C++ exception handling can loop during stacking unwinding in multithreaded programs Date: Sun, 27 Apr 2008 10:53:13 +1000 Yes, obviously it needs the bind lock before it accesses the objs list. As in, Index: rtld.c =================================================================== RCS file: /home/ncvs/root/src/src/libexec/rtld-elf/rtld.c,v retrieving revision 1.124 diff -u -r1.124 rtld.c --- rtld.c 17 May 2007 18:00:27 -0000 1.124 +++ rtld.c 27 Apr 2008 00:51:25 -0000 @@ -2098,9 +2098,10 @@ { struct dl_phdr_info phdr_info; const Obj_Entry *obj; - int error, lockstate; + int error, bind_lockstate, phdr_lockstate; - lockstate = rlock_acquire(rtld_bind_lock); + phdr_lockstate = wlock_acquire(rtld_phdr_lock); + bind_lockstate = rlock_acquire(rtld_bind_lock); error = 0; @@ -2119,7 +2120,8 @@ break; } - rlock_release(rtld_bind_lock, lockstate); + rlock_release(rtld_bind_lock, bind_lockstate); + wlock_release(rtld_phdr_lock, phdr_lockstate); return (error); } Index: rtld_lock.c =================================================================== RCS file: /home/ncvs/root/src/src/libexec/rtld-elf/rtld_lock.c,v retrieving revision 1.4 diff -u -r1.4 rtld_lock.c --- rtld_lock.c 3 Apr 2007 18:28:13 -0000 1.4 +++ rtld_lock.c 27 Apr 2008 00:50:01 -0000 @@ -171,7 +171,7 @@ lockinfo.thread_clr_flag(mask); } -#define RTLD_LOCK_CNT 2 +#define RTLD_LOCK_CNT 3 struct rtld_lock { void *handle; int mask; @@ -179,6 +179,7 @@ rtld_lock_t rtld_bind_lock = &rtld_locks[0]; rtld_lock_t rtld_libc_lock = &rtld_locks[1]; +rtld_lock_t rtld_phdr_lock = &rtld_locks[2]; int rlock_acquire(rtld_lock_t lock) Index: rtld_lock.h =================================================================== RCS file: /home/ncvs/root/src/src/libexec/rtld-elf/rtld_lock.h,v retrieving revision 1.2 diff -u -r1.2 rtld_lock.h --- rtld_lock.h 19 Jun 2003 02:39:37 -0000 1.2 +++ rtld_lock.h 27 Apr 2008 00:50:34 -0000 @@ -52,6 +52,7 @@ extern rtld_lock_t rtld_bind_lock; extern rtld_lock_t rtld_libc_lock; +extern rtld_lock_t rtld_phdr_lock; int rlock_acquire(rtld_lock_t); int wlock_acquire(rtld_lock_t);