d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Consistently use process spin lock for protection of the

Browse Source 
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.

Reported by:	pluknet, pho
Tested by:	pho
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2011-11-18 09:12:26 +00:00
parent dfdda19266
commit 7b5190779b
2 changed files with 7 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
sys/kern/kern_thread.c
View File

@ -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);
}

2
sys/sys/proc.h
View File

@ -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. */