68 lines
2.5 KiB
Diff
68 lines
2.5 KiB
Diff
|
From 39f28eaf8c821d71d57ffc759655ec4168d0bead Mon Sep 17 00:00:00 2001
|
|||
|
|
From: Mark Wielaard <mark@klomp.org>
|
|||
|
|
Date: Thu, 16 Apr 2020 17:45:31 +0200
|
|||
|
|
Subject: [PATCH 2/2] libdwfl: Initialize bits to NULL in
|
|||
|
|
dwfl_standard_find_debuginfo for LTO.
|
|||
|
|
MIME-Version: 1.0
|
|||
|
|
Content-Type: text/plain; charset=UTF-8
|
|||
|
|
Content-Transfer-Encoding: 8bit
|
|||
|
|
|
|||
|
|
GCC10 LTO is too smart (and somewhat cryptic):
|
|||
|
|
|
|||
|
|
find-debuginfo.c: In function ‘dwfl_standard_find_debuginfo’:
|
|||
|
|
debuginfod-client.c:85:8: error: ‘bits’ may be used uninitialized
|
|||
|
|
in this function [-Werror=maybe-uninitialized]
|
|||
|
|
find-debuginfo.c:360:24: note: ‘bits’ was declared here
|
|||
|
|
lto1: all warnings being treated as errors
|
|||
|
|
|
|||
|
|
So it inlines __libdwfl_debuginfod_find_debuginfo into
|
|||
|
|
dwfl_standard_find_debuginfo and since it cannot see into the
|
|||
|
|
function pointer (*fp_debuginfod_find_debuginfo), it assumes that
|
|||
|
|
build_id_bit (== bits in dwfl_standard_find_debuginfo) will be used
|
|||
|
|
by the called function and it might not be initialized.
|
|||
|
|
But if you read the code the there is a check for build_id_len > 0
|
|||
|
|
to see whether bits is or isn't initialized before using bits.
|
|||
|
|
But gcc isn't smart enough to figure that out.
|
|||
|
|
|
|||
|
|
Maybe that actually should be an heuristic gcc lto should use.
|
|||
|
|
If the callchain I am inlining is so deep that I cannot figure out
|
|||
|
|
maybe-uninitialized variables anymore I should stop inlining.
|
|||
|
|
|
|||
|
|
For now just help GCC out and initialize bits to NULL.
|
|||
|
|
|
|||
|
|
Signed-off-by: Mark Wielaard <mark@klomp.org>
|
|||
|
|
---
|
|||
|
|
libdwfl/ChangeLog | 5 +++++
|
|||
|
|
libdwfl/find-debuginfo.c | 2 +-
|
|||
|
|
2 files changed, 6 insertions(+), 1 deletion(-)
|
|||
|
|
|
|||
|
|
diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
|
|||
|
|
index 0b95490..4ddc9ad 100644
|
|||
|
|
--- a/libdwfl/ChangeLog
|
|||
|
|
+++ b/libdwfl/ChangeLog
|
|||
|
|
@@ -1,3 +1,8 @@
|
|||
|
|
+2020-04-16 Mark Wielaard <mark@klomp.org>
|
|||
|
|
+
|
|||
|
|
+ * find-debuginfo.c (dwfl_standard_find_debuginfo): Initialize bits
|
|||
|
|
+ to NULL.
|
|||
|
|
+
|
|||
|
|
2020-01-24 Mark Wielaard <mark@klomp.org>
|
|||
|
|
|
|||
|
|
* linux-kernel-modules.c (find_kernel_elf): Check release isn't NULL.
|
|||
|
|
diff --git a/libdwfl/find-debuginfo.c b/libdwfl/find-debuginfo.c
|
|||
|
|
index 4085764..2dd11c4 100644
|
|||
|
|
--- a/libdwfl/find-debuginfo.c
|
|||
|
|
+++ b/libdwfl/find-debuginfo.c
|
|||
|
|
@@ -357,7 +357,7 @@ dwfl_standard_find_debuginfo (Dwfl_Module *mod,
|
|||
|
|
{
|
|||
|
|
/* First try by build ID if we have one. If that succeeds or fails
|
|||
|
|
other than just by finding nothing, that's all we do. */
|
|||
|
|
- const unsigned char *bits;
|
|||
|
|
+ const unsigned char *bits = NULL;
|
|||
|
|
GElf_Addr vaddr;
|
|||
|
|
int bits_len;
|
|||
|
|
if ((bits_len = INTUSE(dwfl_module_build_id) (mod, &bits, &vaddr)) > 0)
|
|||
|
|
--
|
|||
|
|
1.8.3.1
|
|||
|
|
|