From: Sean Stangl <sstangl@mozilla.com>
Date: Thu, 8 Dec 2016 19:54:24 +0000 (-1000)
Subject: Fix libunwind segfault when -p is passed before -k
X-Git-Tag: v4.15~8
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=54c7792b;p=strace

Fix libunwind segfault when -p is passed before -k

* strace.c (init) [USE_LIBUNWIND]: Call unwind_tcb_init after
unwind_init for all allocated tcb structures if stack trace is enabled.
* unwind.c (unwind_tcb_init): Skip if tcb is already initialized.

Co-authored-by: Dmitry V. Levin <ldv@altlinux.org>
---

diff --git a/strace.c b/strace.c
index 1b8b5cca..56fdfdee 100644
--- a/strace.c
+++ b/strace.c
@@ -1769,8 +1769,14 @@ init(int argc, char *argv[])
 	}
 
 #ifdef USE_LIBUNWIND
-	if (stack_trace_enabled)
+	if (stack_trace_enabled) {
+		unsigned int tcbi;
+
 		unwind_init();
+		for (tcbi = 0; tcbi < tcbtabsize; ++tcbi) {
+			unwind_tcb_init(tcbtab[tcbi]);
+		}
+	}
 #endif
 
 	/* See if they want to run as another user. */
diff --git a/unwind.c b/unwind.c
index 238e215d..326d184e 100644
--- a/unwind.c
+++ b/unwind.c
@@ -103,6 +103,9 @@ unwind_init(void)
 void
 unwind_tcb_init(struct tcb *tcp)
 {
+	if (tcp->libunwind_ui)
+		return;
+
 	tcp->libunwind_ui = _UPT_create(tcp->pid);
 	if (!tcp->libunwind_ui)
 		die_out_of_memory();