From 404d07bb81de01bb0dbd9d21d6e6a2a9b3f89291 Mon Sep 17 00:00:00 2001 From: kib Date: Wed, 23 Nov 2011 15:16:05 +0000 Subject: [PATCH] MFC r227657: Consistently use process spin lock for protection of the p->p_boundary_count. Race could cause the execve(2) from the threaded process to hung since thread boundary counter was incorrect and single-threading never finished. Approved by: re (bz) git-svn-id: svn://svn.freebsd.org/base/releng/9.0@227886 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/kern/kern_thread.c | 7 ++++++- sys/sys/proc.h | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/sys/kern/kern_thread.c b/sys/kern/kern_thread.c index 29bdaa20..d9df5c31 100644 --- a/sys/kern/kern_thread.c +++ b/sys/kern/kern_thread.c @@ -566,6 +566,8 @@ calc_remaining(struct proc *p, int mode) { int remaining; + PROC_LOCK_ASSERT(p, MA_OWNED); + PROC_SLOCK_ASSERT(p, MA_OWNED); if (mode == SINGLE_EXIT) remaining = p->p_numthreads; else if (mode == SINGLE_BOUNDARY) @@ -819,8 +821,11 @@ thread_suspend_check(int return_instead) td->td_flags &= ~TDF_BOUNDARY; thread_unlock(td); PROC_LOCK(p); - if (return_instead == 0) + if (return_instead == 0) { + PROC_SLOCK(p); p->p_boundary_count--; + PROC_SUNLOCK(p); + } } return (0); } diff --git a/sys/sys/proc.h b/sys/sys/proc.h index fb979130..e44caa30 100644 --- a/sys/sys/proc.h +++ b/sys/sys/proc.h @@ -532,7 +532,7 @@ struct proc { struct thread *p_singlethread;/* (c + j) If single threading this is it */ int p_suspcount; /* (j) Num threads in suspended mode. */ struct thread *p_xthread; /* (c) Trap thread */ - int p_boundary_count;/* (c) Num threads at user boundary */ + int p_boundary_count;/* (j) Num threads at user boundary */ int p_pendingcnt; /* how many signals are pending */ struct itimers *p_itimers; /* (c) POSIX interval timers. */ struct procdesc *p_procdesc; /* (e) Process descriptor, if any. */ -- 2.45.0