From 8141ac31ee373b67970c6b8d06a8a003df16845c80ed2e05e2ffbb3a65e89e33 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.com>
Date: Fri, 24 Jan 2020 19:44:43 +0000
Subject: [PATCH] Accepting request 766977 from
 home:tomdevries:branches:devel:tools:compiler-dwz-fix-segfault-die-cu

- Fix segfault in die_cu [swo#25456].
  * dwz-fix-segfault-in-die_cu.patch

OBS-URL: https://build.opensuse.org/request/show/766977
OBS-URL: https://build.opensuse.org/package/show/devel:tools:compiler/dwz?expand=0&rev=28
---
 dwz-fix-segfault-in-die_cu.patch | 55 ++++++++++++++++++++++++++++++++
 dwz.changes                      |  6 ++++
 dwz.spec                         |  2 ++
 3 files changed, 63 insertions(+)
 create mode 100644 dwz-fix-segfault-in-die_cu.patch

diff --git a/dwz-fix-segfault-in-die_cu.patch b/dwz-fix-segfault-in-die_cu.patch
new file mode 100644
index 0000000..9e849a3
--- /dev/null
+++ b/dwz-fix-segfault-in-die_cu.patch
@@ -0,0 +1,55 @@
+Fix segfault in die_cu
+
+[ Backport of master commit e2c440e. ]
+
+When running dwz in normal mode, we get an error:
+...
+$ dwz clang-offload-bundler-10.debug -lnone
+dwz: clang-offload-bundler-10.debug: Couldn't find DIE referenced by \
+  DW_OP_GNU_implicit_pointer
+...
+but when forcing low-mem mode, we get a segfault:
+...
+$ dwz clang-offload-bundler-10.debug -l0
+Segmentation fault (core dumped)
+...
+
+In normal mode, we hit the error here:
+...
+         ref = off_htab_lookup (NULL, addr);
+         if (ref == NULL)
+           {
+             error (0, 0, "%s: Couldn't find DIE referenced by %s",
+                    dso->filename, get_DW_OP_str (op));
+...
+but for low-mem mode, this doesn't trigger, because we find the dummy DIE that
+has been added by read_exprloc_low_mem_phase1.
+
+Fix this by testing for the dummy DIE in the error condition:
+...
+-	  if (ref == NULL)
++	  if (ref == NULL || (unlikely (low_mem) && ref->die_tag == 0))
+...
+
+2020-01-24  Tom de Vries  <tdevries@suse.de>
+
+	PR dwz/25456
+	* dwz.c (read_exprloc): Test for dummy DIE in error condition.
+
+---
+ dwz.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/dwz.c b/dwz.c
+index 298bca1..44b5ba3 100644
+--- a/dwz.c
++++ b/dwz.c
+@@ -1597,7 +1597,7 @@ read_exprloc (DSO *dso, dw_die_ref die, unsigned char *ptr, size_t len,
+ 	  else
+ 	    ptr += 4;
+ 	  ref = off_htab_lookup (NULL, addr);
+-	  if (ref == NULL)
++	  if (ref == NULL || (unlikely (low_mem) && ref->die_tag == 0))
+ 	    {
+ 	      error (0, 0, "%s: Couldn't find DIE referenced by %s",
+ 		     dso->filename, get_DW_OP_str (op));
diff --git a/dwz.changes b/dwz.changes
index 40f051c..c1b43a2 100644
--- a/dwz.changes
+++ b/dwz.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Fri Jan 24 17:08:55 UTC 2020 - Tom de Vries <tdevries@suse.com>
+
+- Fix segfault in die_cu [swo#25456].
+  * dwz-fix-segfault-in-die_cu.patch
+
 -------------------------------------------------------------------
 Fri Jan 17 06:30:58 UTC 2020 - Tom de Vries <tdevries@suse.com>
 
diff --git a/dwz.spec b/dwz.spec
index 5949486..78bc2e3 100644
--- a/dwz.spec
+++ b/dwz.spec
@@ -78,6 +78,7 @@ Patch2:         dwz-fix-die-no-multifile-propagation.patch
 Patch3:         dwz-fix-assertion-off-cu_size-in-recompute_abbrevs.patch
 Patch4:         dwz-fix-refd-NULL-assertion-in-write_die.patch
 Patch5:         dwz-fix-reference-from-pu-to-cu.patch
+Patch6:         dwz-fix-segfault-in-die_cu.patch
 
 %if %{build_main}
 %description
@@ -111,6 +112,7 @@ This package contains the testsuite results from DWZ.
 %patch3 -p1
 %patch4 -p1
 %patch5 -p1
+%patch6 -p1
 
 %build
 make %{?_smp_mflags} CFLAGS="%{optflags}"