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objtool/klp: Fix bug table handling for __WARN_printf()

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Running objtool klp-diff on a changed function which uses WARN() can
fail with:

  vmlinux.o: error: objtool: md_run+0x866: failed to convert reloc sym '__bug_table' to its proper format

The problem is that since commit 5b472b6e5b ("x86_64/bug: Implement
__WARN_printf()"), each __WARN_printf() call site now directly
references its bug table entry.  klp-diff errors out when it can't
convert such section-based references to object symbols (because bug
table entries don't have symbols).

Luckily, klp-diff already has code to create symbols for bug table
entries.  Move that code earlier, before function diffing.

Fixes: dd590d4d57 ("objtool/klp: Introduce klp diff subcommand for diffing object files")
Fixes: 5b472b6e5b ("x86_64/bug: Implement __WARN_printf()")
Reported-by: Song Liu <song@kernel.org>
Tested-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/a8e0a714b9da962858842b9aecd63b4900927c88.1769406850.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
This commit is contained in:
Josh Poimboeuf
2026-01-25 21:56:39 -08:00
parent d107b3265a
commit f2dba60339
1 changed files with 11 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
tools/objtool/klp-diff.c
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@@ -1425,9 +1425,6 @@ static int clone_special_sections(struct elfs *e)
{
struct section *patched_sec;
if (create_fake_symbols(e->patched))
return -1;
for_each_sec(e->patched, patched_sec) {
if (is_special_section(patched_sec)) {
if (clone_special_section(e, patched_sec))
@@ -1704,6 +1701,17 @@ int cmd_klp_diff(int argc, const char **argv)
if (!e.out)
return -1;
/*
* Special section fake symbols are needed so that individual special
* section entries can be extracted by clone_special_sections().
*
* Note the fake symbols are also needed by clone_included_functions()
* because __WARN_printf() call sites add references to bug table
* entries in the calling functions.
*/
if (create_fake_symbols(e.patched))
return -1;
if (clone_included_functions(&e))
return -1;