Fix video playing and network connections in realplayer (and most likely

other stuff) in the osrelease=2.6.16 case:
 - implement CLONE_PARENT semantic
 - fix TLS loading in clone CLONE_SETTLS
 - lock proc in the currently disabled part of CLONE_THREAD

I suggest to not unload the linux module after testing this, there are
some "<defunct>" processes hanging around after exiting (they aren't
with osrelease=2.4.2) and they may panic your kernel when unloading the
linux module. They are in state Z and some of them consume CPU according
to ps. But I don't trust the CPU part, the idle threads gets too much CPU
that this may be possible (accumulating idle, X and 2 defunct processes
results in 104.7%, this looks to much to be a rounding error).

Noticed by:	Intron <mag@intron.ac>
Submitted by:	rdivacky (in collaboration with Intron)
Tested by:	Intron, netchild
Reviewed by:	jhb (previous version)

1 files changed, 11 insertions, 14 deletions

diff --git a/sys/i386/linux/linux_machdep.c b/sys/i386/linux/linux_machdep.c
index 4bb457b..73fa345 100644
--- a/sys/i386/linux/linux_machdep.c
+++ b/sys/i386/linux/linux_machdep.c
@@ -414,24 +414,24 @@ linux_clone(struct thread *td, struct linux_clone_args *args)
 		}
 	}
 
-	if (args->flags & CLONE_PARENT) {
-#ifdef DEBUG
-	   	printf("linux_clone: CLONE_PARENT\n");
-#endif
+	if (args->flags & (CLONE_PARENT|CLONE_THREAD)) {
+	   	sx_xlock(&proctree_lock);
+		PROC_LOCK(p2);
+		proc_reparent(p2, td->td_proc->p_pptr);
+		PROC_UNLOCK(p2);
+		sx_xunlock(&proctree_lock);
 	}
-	   	
+
 	if (args->flags & CLONE_THREAD) {
 	   	/* XXX: linux mangles pgrp and pptr somehow
 		 * I think it might be this but I am not sure.
 		 */
 #ifdef notyet
+	   	PROC_LOCK(p2);
 	   	p2->p_pgrp = td->td_proc->p_pgrp;
-	 	p2->p_pptr = td->td_proc->p_pptr;
+	   	PROC_UNLOCK(p2);
 #endif
 	 	exit_signal = 0;
-#ifdef DEBUG
-	   	printf("linux_clone: CLONE_THREADS\n");
-#endif
 	}
 
 	if (args->flags & CLONE_CHILD_SETTID)
@@ -443,6 +443,7 @@ linux_clone(struct thread *td, struct linux_clone_args *args)
 		em->child_clear_tid = args->child_tidptr;
 	else
 	   	em->child_clear_tid = NULL;
+
 	EMUL_UNLOCK(&emul_lock);
 
 	PROC_LOCK(p2);
@@ -502,13 +503,9 @@ linux_clone(struct thread *td, struct linux_clone_args *args)
 			sd.sd_gran);
 #endif
 
-		/* this is taken from i386 version of cpu_set_user_tls() */
-		critical_enter();
 		/* set %gs */
 		td2->td_pcb->pcb_gsd = sd;
-		PCPU_GET(fsgs_gdt)[1] = sd;
-		load_gs(GSEL(GUGS_SEL, SEL_UPL));
-		critical_exit();
+		td2->td_pcb->pcb_gs = GSEL(GUGS_SEL, SEL_UPL);
 	} 
 
 #ifdef DEBUG