Attachment 187941 Details for Bug 201276 – Special case traced pdfork processes in wait6

[patch] Special case traced pdfork processes in wait6

special-case-traced-procs-in-wait6.patch (text/plain), 3.80 KB, created by Jan Kokemüller on 2017-11-12 15:15:22 UTC

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Creator: Jan Kokemüller

Created: 2017-11-12 15:15:22 UTC

Size: 3.80 KB

patch

obsolete

>diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
>index d05951e150c8..4a9af5be583e 100644
>--- a/sys/kern/kern_exit.c
>+++ b/sys/kern/kern_exit.c
>@@ -337,6 +337,9 @@ exit1(struct thread *td, int rval, int signo)
> 	 */
> 	PROC_LOCK(p);
> 	stopprofclock(p);
>+	if (p->p_flag & P_TRACED) {
>+		p->p_flag2 |= P2_P_ALL_NOTI;
>+	}
> 	p->p_flag &= ~(P_TRACED | P_PPWAIT | P_PPTRACE);
> 	p->p_ptevents = 0;
> 
>@@ -559,7 +562,8 @@ exit1(struct thread *td, int rval, int signo)
> 	 * procdesc_exit() to serialize concurrent calls to close() and
> 	 * exit().
> 	 */
>-	if (p->p_procdesc == NULL || procdesc_exit(p)) {
>+	if (p->p_procdesc == NULL || procdesc_exit(p) ||
>+	    (p->p_flag & P_TRACED)) {
> 		/*
> 		 * Notify parent that we're gone.  If parent has the
> 		 * PS_NOCLDWAIT flag set, or if the handler is set to SIG_IGN,
>@@ -951,7 +955,15 @@ proc_to_reap(struct thread *td, struct proc *p, idtype_t idtype, id_t id,
> 
> 	switch (idtype) {
> 	case P_ALL:
>-		if (p->p_procdesc != NULL) {
>+		/*
>+		 * Usually, processes created with pdfork(2) should be
>+		 * invisible to wait(2) when using P_ALL. However, ptrace(2) in
>+		 * PTRACE_FORK mode does not know whether a process was created
>+		 * by pdfork(2) or fork(2) and expects the tracing process
>+		 * to deal with the new process in its event loop.
>+		 */
>+		if (p->p_procdesc != NULL && !(p->p_flag & P_TRACED) &&
>+		    !(p->p_flag2 & P2_P_ALL_NOTI)) {
> 			PROC_UNLOCK(p);
> 			return (0);
> 		}
>diff --git a/sys/kern/sys_procdesc.c b/sys/kern/sys_procdesc.c
>index 5f2c9ec69805..ab0d31a536da 100644
>--- a/sys/kern/sys_procdesc.c
>+++ b/sys/kern/sys_procdesc.c
>@@ -399,26 +399,35 @@ procdesc_close(struct file *fp, struct thread *td)
> 			PROC_SLOCK(p);
> 			proc_reap(curthread, p, NULL, 0);
> 		} else {
>-			/*
>-			 * If the process is not yet dead, we need to kill it,
>-			 * but we can't wait around synchronously for it to go
>-			 * away, as that path leads to madness (and deadlocks).
>-			 * First, detach the process from its descriptor so that
>-			 * its exit status will be reported normally.
>-			 */
>-			pd->pd_proc = NULL;
>-			p->p_procdesc = NULL;
>-			procdesc_free(pd);
>+			/* we don't need to do the following if we are already
>+			 * exiting */
>+			if (!(p->p_flag & P_WEXIT)) {
>+				/*
>+				 * If the process is not yet dead, we need to
>+				 * kill it, but we can't wait around
>+				 * synchronously for it to go away, as that
>+				 * path leads to madness (and deadlocks).
>+				 * First, detach the process from its
>+				 * descriptor so that its exit status will be
>+				 * reported normally.
>+				 */
>+				pd->pd_proc = NULL;
>+				p->p_procdesc = NULL;
>+				procdesc_free(pd);
>+
>+				/*
>+				 * Next, reparent it to init(8) so that there's
>+				 * someone to pick up the pieces; finally,
>+				 * terminate with prejudice.
>+				 */
>+				p->p_sigparent = SIGCHLD;
>+				if (!(p->p_flag & P_TRACED)) {
>+					proc_reparent(p, initproc);
>+				}
>+				if ((pd->pd_flags & PDF_DAEMON) == 0)
>+					kern_psignal(p, SIGKILL);
>+			}
> 
>-			/*
>-			 * Next, reparent it to init(8) so that there's someone
>-			 * to pick up the pieces; finally, terminate with
>-			 * prejudice.
>-			 */
>-			p->p_sigparent = SIGCHLD;
>-			proc_reparent(p, initproc);
>-			if ((pd->pd_flags & PDF_DAEMON) == 0)
>-				kern_psignal(p, SIGKILL);
> 			PROC_UNLOCK(p);
> 			sx_xunlock(&proctree_lock);
> 		}
>diff --git a/sys/sys/proc.h b/sys/sys/proc.h
>index 2daf1a6aee7d..24434994bab8 100644
>--- a/sys/sys/proc.h
>+++ b/sys/sys/proc.h
>@@ -730,6 +730,7 @@ struct proc {
> #define	P2_AST_SU	0x00000008	/* Handles SU ast for kthreads. */
> #define	P2_PTRACE_FSTP	0x00000010 /* SIGSTOP from PT_ATTACH not yet handled. */
> #define	P2_TRAPCAP	0x00000020	/* SIGTRAP on ENOTCAPABLE */
>+#define	P2_P_ALL_NOTI	0x00000040 /* force notification in wait(2) P_ALL */
> 
> /* Flags protected by proctree_lock, kept in p_treeflags. */
> #define	P_TREE_ORPHANED		0x00000001	/* Reparented, on orphan list */

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Attachments on bug 201276: 187941 | 198099