On Fri, Dec 12, 2003 at 08:53:15PM +0900, YAMAMOTO Takashi wrote:
> hi,
> 
> > Module Name:	src
> > Committed By:	dsl
> > Date:		Wed Nov 12 21:07:38 UTC 2003
> > 
> > Modified Files:
> > 	src/sys/compat/svr4: svr4_misc.c
> > 	src/sys/compat/svr4_32: svr4_32_misc.c
> > 	src/sys/kern: kern_exec.c kern_exit.c kern_fork.c kern_ktrace.c
> > 	    kern_proc.c kern_sig.c
> > 	src/sys/sys: param.h proc.h
> > 
> > Log Message:
> > - Count number of zombies and stopped children and requeue them at the top
> >   of the sibling list so that find_stopped_child can be optimised to avoid
> >   traversing the entire sibling list - helps when a process has a lot of
> >   children.
> > - Modify locking in pfind() and pgfind() to that the caller can rely on the
> >   result being valid, allow caller to request that zombies be findable.
> > - Rename pfind() to p_find() to ensure we break binary compatibility.
> > - Remove svr4_pfind since p_find willnow do the job.
> > - Modify some of the SMP locking of the proc lists - signals are still stuffed.
> > 
> > Welcome to 1.6ZF
> 
> this change seems to break ktrace.
> now ktrace_common() calls ktrops(), which might sleep,
> with proclist lock held.

The fix below should fix this by deferring the trace of the EMUL line
until the relevant process is active.

There is still a problem if fclose(9) sleeps - but that needs a different fix.

	David

Index: sys/ktrace.h
===================================================================
RCS file: /cvsroot/src/sys/sys/ktrace.h,v
retrieving revision 1.35
diff -u -p -r1.35 ktrace.h
--- sys/ktrace.h	2003/11/24 16:51:33	1.35
+++ sys/ktrace.h	2003/12/14 20:45:26
@@ -212,6 +212,7 @@ struct ktr_mool {
 #define KTRFAC_ROOT	0x80000000	/* root set this trace */
 #define KTRFAC_INHERIT	0x40000000	/* pass trace flags to children */
 #define KTRFAC_ACTIVE	0x20000000	/* ktrace logging in progress, ignore */
+#define KTRFAC_TRC_EMUL	0x10000000	/* ktrace KTR_EMUL before next trace */
 
 #ifndef	_KERNEL
 
Index: kern/kern_ktrace.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_ktrace.c,v
retrieving revision 1.83
diff -u -p -r1.83 kern_ktrace.c
--- kern/kern_ktrace.c	2003/11/24 16:51:33	1.83
+++ kern/kern_ktrace.c	2003/12/14 20:45:28
@@ -677,7 +677,7 @@ ktrops(curp, p, ops, facs, fp)
 	 * change/attach request. 
 	 */
 	if (KTRPOINT(p, KTR_EMUL))
-		ktremul(p);
+		p->p_traceflag |= KTRFAC_TRC_EMUL;
 #ifdef __HAVE_SYSCALL_INTERN
 	(*p->p_emul->e_syscall_intern)(p);
 #endif
@@ -734,6 +734,12 @@ ktrwrite(p, kth)
 	if (fp == NULL)
 		return 0;
 	
+	if (p->p_traceflag & KTRFAC_TRC_EMUL) {
+		/* Add emulation trace before first entry for this process */
+		p->p_traceflag &= ~KTRFAC_TRC_EMUL;
+		ktremul(p);
+	}
+
 	auio.uio_iov = &aiov[0];
 	auio.uio_offset = 0;
 	auio.uio_segflg = UIO_SYSSPACE;

-- 
David Laight: david@l8s.co.uk