From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 4A40836492A; Mon, 3 Aug 2026 03:24:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785727491; cv=none; b=gIRKGXB9AdTp2rHbw7QDw0i8oBMxagq88RaSAxbbntVV27LZeV79BexCXCYiqRDQerW70RHiJFSypRfOJSJm7B0YUTi4zpIK2ykb84J2abGz+GsXB8F14HcvrkTw+DK5THxvOSlT6HYBkILOC1HONKW8J2MgKdtaNotVXC+342g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785727491; c=relaxed/simple; bh=hm3D/Xty8MBZM3QfRbUzA8YpbzAJCtUKOyJdYd95Ovo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=I9kN9bSrTZoA/uhTqXtwD3iP4Z0/ncqfGPDgzYh5f8uMjqjmHzP0Yqp9bSxCAFx9+OIRI5R1EsoTZQruLqxB/MIK9zdYjv35fbBYJrP/WOacPE9lwzJBM2WdbLPXttxNd1zfMwF4hc/ASl+cCfw4duA2NcFKsD2BeF4WyWseI2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iQTPu1Wi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iQTPu1Wi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60DC31F00A3F; Mon, 3 Aug 2026 03:24:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785727489; bh=7remyKREYUVeFS3QYdwJSO3fUjTHDVOdeo5ZoWSgbRg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iQTPu1WiC9tor+Sm1inMIHJPO7FNi+HIpRCyi58OrI0trvey27NJvz/41hc1q6Pi5 oi8FRITIKpGnBsnz5ka9z8wYzvwtk9yDQpdp9apD4NdpJ+2cGjH03hcjKEGlK1tTG0 yhOjI+1DFiu34j3JmgGKC/pq+Z/z6gu8Vs1TILeyHmJeRh/VZHRUt87D0jhC7qXQEW rz6x1joInJZAiEG8u9osnDIJ4dk0YMPUesmbh8hutYlVwKTug19k9/yxLgqvO81fpi dx1er5v2Aks54l/E8oHvinuz2Dit2HxeEamwAN4T60XtQR2ara2W6E9rc/Vbza5SCz Lu4efUw274v1w== From: Josh Poimboeuf To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Peter Zijlstra , Joe Lawrence , Miroslav Benes , Petr Mladek , Song Liu , Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , linux-modules@vger.kernel.org, Ben Procknow Subject: [PATCH 02/14] objtool/klp: Normalize Module.symvers paths to module names Date: Sun, 2 Aug 2026 20:24:24 -0700 Message-ID: X-Mailer: git-send-email 2.54.0 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: 8bit From: Joe Lawrence Module.symvers contains build-tree object paths as module identifiers (e.g., "arch/x86/kvm/kvm") rather than runtime module names ("kvm"). Objtool's clone_reloc_klp() uses this field directly for exported symbols, while unexported symbols correctly go through __find_modname(). This means that exported symbol relocations may land in a .klp.rela section named with the build path rather than the module name. That is a crash waiting to happen: the kernel's livepatch loader silently skips this relocation because it doesn't match the expected klp_object name. The unresolved relocation sits in the newly activated code, crashing when executed. Normalize export->mod at Module.symvers read time using the same logic as __find_modname() (refactored into a shared normalize_modname() helper). Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files") Reported-by: Ben Procknow Signed-off-by: Joe Lawrence Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf --- tools/objtool/klp-diff.c | 49 ++++++++++++++++++++++++++++------------ 1 file changed, 34 insertions(+), 15 deletions(-) diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c index aeb99d572300..15d37d955af0 100644 --- a/tools/objtool/klp-diff.c +++ b/tools/objtool/klp-diff.c @@ -83,6 +83,35 @@ static char *escape_str(const char *orig) return new; } +/* + * Convert a build-tree object path to a runtime module name: strip + * directory components, replace '-' with '_', and remove file + * extensions. Examples: + * + * "arch/x86/kvm/kvm" -> "kvm" + * "arch/x86/kvm/kvm-intel" -> "kvm_intel". + * + * Used by read_exports() to normalize Module.symvers entries and by + * __find_modname() as a fallback when .modinfo lacks a "name=" tag. + */ +static char *normalize_modname(char *name) +{ + char *slash = strrchr(name, '/'); + + if (slash) + name = slash + 1; + + for (char *c = name; *c; c++) { + if (*c == '-') + *c = '_'; + else if (*c == '.') { + *c = '\0'; + break; + } + } + return name; +} + static int read_exports(void) { const char *symvers = "Module.symvers"; @@ -150,6 +179,9 @@ static int read_exports(void) return -1; } + if (strcmp(export->mod, "vmlinux")) + export->mod = normalize_modname(export->mod); + export->sym = strdup(sym); if (!export->sym) { ERROR_GLIBC("strdup"); @@ -1140,7 +1172,7 @@ static struct export *find_export(struct symbol *sym) static const char *__find_modname(struct elfs *e) { struct section *sec; - char *name, *slash; + char *name; sec = find_section_by_name(e->orig, ".modinfo"); if (!sec) { @@ -1158,20 +1190,7 @@ static const char *__find_modname(struct elfs *e) return NULL; } - slash = strrchr(name, '/'); - if (slash) - name = slash + 1; - - for (char *c = name; *c; c++) { - if (*c == '-') - *c = '_'; - else if (*c == '.') { - *c = '\0'; - break; - } - } - - return name; + return normalize_modname(name); } /* Get the object's module name as defined by the kernel (and klp_object) */ -- 2.54.0