From 69b2c33a77fa687feb41fafdbe187013aa812384 Mon Sep 17 00:00:00 2001

From: "Dmitry V. Levin" <ldv@altlinux.org>

Date: Tue, 7 Jan 2020 18:54:55 +0000

Subject: [PATCH] unwind-libdw: fix initialization of libdwfl cache

This fixes stack trace printing for early syscalls that precede

the first syscall from memory mapping or execve families.

* unwind-libdw.c (tcb_init): Set struct ctx.last_proc_updating

to a value different from mapping_generation so that libdwfl cache

is properly initialized before the first use.

* NEWS: Mention this fix.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1788636

---

Backport changes:

 - NEWS hunk has been dropped.

---

 NEWS           | 2 ++

 unwind-libdw.c | 2 +-

 2 files changed, 3 insertions(+), 1 deletion(-)

Index: strace-4.24/unwind-libdw.c

===================================================================

--- strace-4.24.orig/unwind-libdw.c	2020-01-23 12:55:01.922338273 +0100

+++ strace-4.24/unwind-libdw.c	2020-01-23 12:55:06.131299136 +0100

@@ -69,7 +69,7 @@

 	struct ctx *ctx = xmalloc(sizeof(*ctx));

 	ctx->dwfl = dwfl;

-	ctx->last_proc_updating = 0;

+	ctx->last_proc_updating = mapping_generation - 1;

 	return ctx;

 }