From: Denys Vlasenko <dvlasenk@redhat.com>
Date: Fri, 21 Jun 2013 13:50:41 +0000 (+0200)
Subject: Eat pending SIGSTOP _before_ PTRACE_DETACH in detach()
X-Git-Tag: v4.9~230
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a2de9dacec47b7902b19f37edcc564faff346816;p=strace

Eat pending SIGSTOP _before_ PTRACE_DETACH in detach()

* strace.c (detach): If TCB_IGNORE_ONE_SIGSTOP is set,
di not PTRACE_DETACH - wait for SIGSTOP first.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
---

diff --git a/strace.c b/strace.c
index 89e89bc3..55089bf3 100644
--- a/strace.c
+++ b/strace.c
@@ -758,6 +758,8 @@ detach(struct tcb *tcp)
 		 * would be left stopped (process state T).
 		 */
 		sigstop_expected = (tcp->flags & TCB_IGNORE_ONE_SIGSTOP);
+		if (sigstop_expected)
+			goto wait_loop;
 		error = ptrace(PTRACE_DETACH, tcp->pid, 0, 0);
 		if (error == 0) {
 			/* On a clear day, you can see forever. */
@@ -802,6 +804,7 @@ detach(struct tcb *tcp)
 	}
 
 	if (sigstop_expected || interrupt_done) {
+ wait_loop:
 		for (;;) {
 			int sig;
 			if (waitpid(tcp->pid, &status, __WALL) < 0) {