Thread (13 messages) flat view 13 messages, 4 authors, 2d ago

Re: [PATCH v3 1/2] module: pull out add_taint_module() to be public

From: Petr Pavlu <petr.pavlu@suse.com>
Date: 2026-09-04 09:25:05
Also in: driver-core, linux-doc, linux-modules, linux-usb, lkml

On 9/4/26 7:10 AM, Greg Kroah-Hartman wrote:
quoted hunk ↗ jump to hunk
Other kernel code might want to call add_taint_module() so pull it out
and make it global.  If modules are not enabled, this defaults to a call
to add_taint(), so all is fine.

Reviewed-by: Johan Hovold <johan@kernel.org>
Tested-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Bradley Morgan <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/module.h | 10 ++++++++++
 kernel/module/main.c   | 16 +++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 96cc98568eea..f6f90cd88f15 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -29,6 +29,7 @@
 #include <linux/srcu.h>
 #include <linux/static_call_types.h>
 #include <linux/dynamic_debug.h>
+#include <linux/panic.h>
Note that I'm working on cleaning up linux/module.h to reduce its
preprocessed size. The main motivation is to shorten the compilation
time of all the small *.mod.c files. Since linux/module.h already
includes linux/panic.h indirectly, adding this include explicitly seems
fine to me for now. In the future, I think we should introduce something
like kernel/module/stubs.c where the CONFIG_MODULES=n variants of
add_taint_module() and other similar functions can live without bloating
linux/module.h.
quoted hunk ↗ jump to hunk
 
 #include <linux/percpu.h>
 #include <asm/module.h>
@@ -770,6 +771,9 @@ static inline bool is_livepatch_module(struct module *mod)
 
 void module_for_each_mod(int(*func)(struct module *mod, void *data), void *data);
 
+void add_taint_module(struct module *mod, unsigned flag,
+		      enum lockdep_ok lockdep_ok);
+
 #else /* !CONFIG_MODULES... */
 
 static inline struct module *__module_address(unsigned long addr)
@@ -877,6 +881,12 @@ static inline bool module_is_coming(struct module *mod)
 static inline void module_for_each_mod(int(*func)(struct module *mod, void *data), void *data)
 {
 }
+
+static inline void add_taint_module(struct module *mod, unsigned flag,
+				    enum lockdep_ok lockdep_ok)
+{
+	add_taint(flag, lockdep_ok);
+}
 #endif /* CONFIG_MODULES */
 
 #ifdef CONFIG_SYSFS
diff --git a/kernel/module/main.c b/kernel/module/main.c
index d0e1e0bd2ad0..444d990c9983 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -191,11 +191,21 @@ static inline int strong_try_module_get(struct module *mod)
 		return -ENOENT;
 }
 
-static inline void add_taint_module(struct module *mod, unsigned flag,
-				    enum lockdep_ok lockdep_ok)
+/**
+ * add_taint_module: add a taint flag if not already set for a specific module
+ * @mod: pointer to the module that caused the problem
+ * @flag: one of the TAINT_* constants.
+ * @lockdep_ok: whether lock debugging is still OK.
+ *
+ * If something bad has gone wrong, you'll want @lockdebug_ok = false, but for
+ * some noteworthy-but-not-corrupting cases, it can be set to true.
Nit: The final paragraph is mostly copied from the description of
add_taint() but I don't think it is quite right. The parameter name
should be lockdep_ok, not lockdebug_ok and the values are
LOCKDEP_STILL_OK / LOCKDEP_NOW_UNRELIABLE, not true / false.

I suggest updating this part for both add_taint() and add_taint_module()
to something like:

 * Use @lockdep_ok = LOCKDEP_NOW_UNRELIABLE if something serious has gone wrong.
 * For noteworthy but non-corrupting cases, use LOCKDEP_STILL_OK instead.
+ */
+void add_taint_module(struct module *mod, unsigned flag,
+		      enum lockdep_ok lockdep_ok)
 {
 	add_taint(flag, lockdep_ok);
-	set_bit(flag, &mod->taints);
+	if (mod)
+		set_bit(flag, &mod->taints);
 }
 
 /*
Otherwise, this looks ok to me. Feel free to add:

Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>

-- 
Thanks,
Petr
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