linux-kernel - [PATCH] module: show disallowed symbol name for inherit

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Date:   Tue, 26 Apr 2022 12:21:20 +0800
From:   Lecopzer Chen <lecopzer.chen@...iatek.com>
To:     Luis Chamberlain <mcgrof@...nel.org>,
        <linux-kernel@...r.kernel.org>
CC:     Matthias Brugger <matthias.bgg@...il.com>,
        <linux-modules@...r.kernel.org>,
        <linux-mediatek@...ts.infradead.org>, <yj.chiang@...iatek.com>,
        <lecopzer.chen@...iatek.com>
Subject: [PATCH] module: show disallowed symbol name for inherit_taint()

The error log for inherit_taint() doesn't really help to find the symbols
which violate GPL rules.

For example,
if a module has 50 disallowed symbols, the log only shows the content below
and is duplicated with 50 lines.
    AAA: module using GPL-only symbols uses symbols from proprietary module BBB.
    AAA: module using GPL-only symbols uses symbols from proprietary module BBB.
    ...

This patch add symbol name to tell the offending symbols explicitly.

To-be:
    AAA: module using GPL-only symbols uses symbols SS1 from proprietary module BBB.
    AAA: module using GPL-only symbols uses symbols SS2 from proprietary module BBB.
    ...

Signed-off-by: Lecopzer Chen <lecopzer.chen@...iatek.com>
---
 kernel/module.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 6cea788fd965..30973f0d2b7c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1372,20 +1372,20 @@ static int verify_namespace_is_imported(const struct load_info *info,
 	return 0;
 }
 
-static bool inherit_taint(struct module *mod, struct module *owner)
+static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
 {
 	if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
 		return true;
 
 	if (mod->using_gplonly_symbols) {
-		pr_err("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
-			mod->name, owner->name);
+		pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
+			mod->name, name, owner->name);
 		return false;
 	}
 
 	if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
-		pr_warn("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
-			mod->name, owner->name);
+		pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
+			mod->name, name, owner->name);
 		set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
 	}
 	return true;
@@ -1417,7 +1417,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	if (fsa.license == GPL_ONLY)
 		mod->using_gplonly_symbols = true;
 
-	if (!inherit_taint(mod, fsa.owner)) {
+	if (!inherit_taint(mod, fsa.owner, name)) {
 		fsa.sym = NULL;
 		goto getname;
 	}
-- 
2.18.0