linux-kernel - Re: "Unloaded tainted modules:" prints repeated wrong value

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Message-ID: <20221006163809.6gzl23ylu36gerli@ava.usersys.com>
Date:   Thu, 6 Oct 2022 17:38:09 +0100
From:   Aaron Tomlin <atomlin@...hat.com>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     mcgrof@...nel.org, linux-kernel@...r.kernel.org,
        linux-modules@...r.kernel.org
Subject: Re: "Unloaded tainted modules:" prints repeated wrong value

On Tue 2022-10-04 15:47 +0300, Alexey Dobriyan wrote:
> I got obiously incorrect values of "pcc_cpufreq():1" on a clean kernel
> and clean oops (see below). Original oops is different bug.

Hi Alexey,

[Added Luis Chamberlain and linux-modules@...r.kernel.org on Cc]

Sorry about that!

Indeed, in the context of the module deletion code path, no module
record/or entry should be added to 'unloaded_tainted_modules' if
the module does not carry a taint. I will send a patch shortly.
The following solution should be sufficient:

diff --git a/kernel/module/tracking.c b/kernel/module/tracking.c
index 7f8133044d09..af52cabfe632 100644
--- a/kernel/module/tracking.c
+++ b/kernel/module/tracking.c
@@ -21,6 +21,9 @@ int try_add_tainted_module(struct module *mod)
 
 	module_assert_mutex_or_preempt();
 
+	if (!mod->taints)
+		goto out;
+
 	list_for_each_entry_rcu(mod_taint, &unloaded_tainted_modules, list,
 				lockdep_is_held(&module_mutex)) {
 		if (!strcmp(mod_taint->name, mod->name) &&



Kind regards,

-- 
Aaron Tomlin