[PATCH] dwarves: Initialize cu->priv explicitly

["Thomas Weißschuh" <thomas@t-8ch.de>]

Otherweise ->priv may contain garbage data.
This triggers a bug where the BTF loader thinks that the private data
has been set and wants to free it, crashing the program.

The bug is not reproducible with all binaries. A test file is
/usr/lib/libevdev.so.2.3.0 from
https://archive.archlinux.org/packages/l/libevdev/libevdev-1.11.0-1-x86_64.pkg.tar.zst

Stacktrace:
 Program terminated with signal SIGSEGV, Segmentation fault.
 #0  0x00007f0c4cacfc49 in btf__free (btf=0x20) at lib/bpf/src/btf.c:729
 729		if (btf->fd >= 0)
 #1  0x00007f0c4cac2d20 in btf__cu_delete (cu=0x555d89203670) at btf_loader.c:536
 #2  0x00007f0c4caaca44 in cu__delete (cu=0x555d89203670) at dwarves.c:630
 #3  0x00007f0c4cac2f4d in cus__load_btf (cus=0x555d89203140, conf=0x555d8863f360 <conf_load>,
     filename=0x7fff8fb8327e "/usr/lib/libevdev.so.2.3.0") at btf_loader.c:595
 #4  0x00007f0c4caafc18 in cus__load_file (cus=0x555d89203140, conf=0x555d8863f360 <conf_load>,
     filename=0x7fff8fb8327e "/usr/lib/libevdev.so.2.3.0") at dwarves.c:1993
 #5  0x00007f0c4cab0988 in cus__load_files (cus=0x555d89203140, conf=0x555d8863f360 <conf_load>,
     filenames=0x7fff8fb815f0) at dwarves.c:2352
 #6  0x0000555d88638d6d in main (argc=2, argv=0x7fff8fb815e8) at pahole.c:2842

Fixes: 7fb31d787d3deec191527ca010c74888f4acd765 btf_loader: Stop using libbtf.h and the btf_elf class
Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---
 dwarves.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/dwarves.c b/dwarves.c
index 34f581d..ed0037d 100644
--- a/dwarves.c
+++ b/dwarves.c
@@ -576,6 +576,8 @@ struct cu *cu__new(const char *name, uint8_t addr_size,
 		if (cu->filename == NULL)
 			goto out_free_name;
 
+		cu->priv = NULL;
+
 		ptr_table__init(&cu->tags_table);
 		ptr_table__init(&cu->types_table);
 		ptr_table__init(&cu->functions_table);

base-commit: 3ec54ee72ff7c5b169252972f69007b54e2f9211
-- 
2.32.0