From nobody Thu Apr 2 17:10:49 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3463D33987D; Tue, 10 Feb 2026 21:50:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770760226; cv=none; b=nYLT0vQRoipV7Z3cdB55KnOThkfrw92g5VF4AlBgDSM1AQtrPEU1372QwfGkMtbs9rJg4SJUqm9JstvpOuo+sc9L+1LKo/gUGDosTOUbLkFPLhM/oVRn8l35fGXwI/oXQoqFvOFaAfFcSG0/B3fcMX0MBUCtm9GB03sfSFZnzO0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770760226; c=relaxed/simple; bh=9EOLe2PSxvdepkarQnhpJpYsJ/R0HZPuyMwQs1cmanM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KC89moKolJdNrhOJYOlAzIFUt/lsnANWytW1JtCKuVPt34XgA4/GQJPY7c7SZhL1YFSZDKEAAhWJdvyTmyVNMqhjC1mBqFIRaWb+Lqwupnvw6zsBYMFtcn4IvJA6jevPZgCsKg1EdmV6JxypfXIh/MLO+yDnnSb+4bz2oaDaxzM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qNZy+SBY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qNZy+SBY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C685DC2BCB5; Tue, 10 Feb 2026 21:50:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770760226; bh=9EOLe2PSxvdepkarQnhpJpYsJ/R0HZPuyMwQs1cmanM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qNZy+SBYiZA0PdZPDSuQCg7fHyTSPOc/VawZXC5YGYz8Vbd4bFS0yLa7IVAfd/zj3 ZaW+ZLpBpN+ISzBmDqBnivJtJZZu6cjXTBE7Aw1U6sRWT/ubv4jEvVR4JPFN1jzghR eeOuWI5aqmjefZey1DS1/xzyQkE9fGuzm6SYdYeRZyToHR9T/VO4DdgySKizcvoJp0 KWo+6vArMJAT4Cd3JiBsDaX0cvq+NfC4IH+2lDxvMtWiprr17lDktmRXIlh5tuYHNc sUcooMq+oWW9I5nfBY0EyEU0UKwCfqTUzbADsda2loke8ZDhYbJMRL7wx4bCBuxhlT dmZMYBsp05nSg== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , live-patching@vger.kernel.org, Song Liu , Joe Lawrence Subject: [PATCH 3/3] objtool/klp: Avoid NULL pointer dereference when printing code symbol name Date: Tue, 10 Feb 2026 13:50:11 -0800 Message-ID: <64116517bc93851a98fe366ea0a4d807f4c70aab.1770759954.git.jpoimboe@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Fix a hypothetical NULL pointer defereference of the 'code_sym' variable. In theory this should never happen. Signed-off-by: Josh Poimboeuf --- tools/objtool/klp-diff.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index 9ff65b01882b..a3198a63c2f0 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -1352,7 +1352,7 @@ static int validate_special_section_klp_reloc(struct = elfs *e, struct symbol *sym { bool static_branch =3D !strcmp(sym->sec->name, "__jump_table"); bool static_call =3D !strcmp(sym->sec->name, ".static_call_sites"); - struct symbol *code_sym =3D NULL; + const char *code_sym =3D NULL; unsigned long code_offset =3D 0; struct reloc *reloc; int ret =3D 0; @@ -1372,7 +1372,7 @@ static int validate_special_section_klp_reloc(struct = elfs *e, struct symbol *sym =20 /* Save code location which can be printed below */ if (reloc->sym->type =3D=3D STT_FUNC && !code_sym) { - code_sym =3D reloc->sym; + code_sym =3D reloc->sym->name; code_offset =3D reloc_addend(reloc); } =20 @@ -1395,23 +1395,26 @@ static int validate_special_section_klp_reloc(struc= t elfs *e, struct symbol *sym if (!strcmp(sym_modname, "vmlinux")) continue; =20 + if (!code_sym) + code_sym =3D ""; + if (static_branch) { if (strstarts(reloc->sym->name, "__tracepoint_")) { WARN("%s: disabling unsupported tracepoint %s", - code_sym->name, reloc->sym->name + 13); + code_sym, reloc->sym->name + 13); ret =3D 1; continue; } =20 if (strstr(reloc->sym->name, "__UNIQUE_ID_ddebug_")) { WARN("%s: disabling unsupported pr_debug()", - code_sym->name); + code_sym); ret =3D 1; continue; } =20 ERROR("%s+0x%lx: unsupported static branch key %s. Use static_key_enab= led() instead", - code_sym->name, code_offset, reloc->sym->name); + code_sym, code_offset, reloc->sym->name); return -1; } =20 @@ -1422,7 +1425,7 @@ static int validate_special_section_klp_reloc(struct = elfs *e, struct symbol *sym } =20 ERROR("%s()+0x%lx: unsupported static call key %s. Use KLP_STATIC_CALL(= ) instead", - code_sym->name, code_offset, reloc->sym->name); + code_sym, code_offset, reloc->sym->name); return -1; } =20 --=20 2.53.0