linux-kernel - [PATCH v2 1/3] module: Modify module_flags() to accept show

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Message-Id: <20220714153933.2095776-2-atomlin@redhat.com>
Date:   Thu, 14 Jul 2022 16:39:31 +0100
From:   Aaron Tomlin <atomlin@...hat.com>
To:     mcgrof@...nel.org, christophe.leroy@...roup.eu
Cc:     linux-kernel@...r.kernel.org, linux-modules@...r.kernel.org,
        atomlin@...mlin.com, oleksandr@...alenko.name, neelx@...hat.com
Subject: [PATCH v2 1/3] module: Modify module_flags() to accept show_state argument

No functional change.

With this patch a given module's state information (i.e. 'mod->state')
can be omitted from the specified buffer. Please note that this is in
preparation to include the last unloaded module's taint flag(s),
if available.

Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
---
 kernel/module/internal.h |  2 +-
 kernel/module/main.c     | 11 +++++++----
 kernel/module/procfs.c   |  2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index bc5507ab8450..60312f23c7d0 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -100,7 +100,7 @@ struct module *find_module_all(const char *name, size_t len, bool even_unformed)
 int cmp_name(const void *name, const void *sym);
 long module_get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr,
 		       unsigned int section);
-char *module_flags(struct module *mod, char *buf);
+char *module_flags(struct module *mod, char *buf, bool show_state);
 size_t module_flags_taint(unsigned long taints, char *buf);
 
 static inline void module_assert_mutex_or_preempt(void)
diff --git a/kernel/module/main.c b/kernel/module/main.c
index fed58d30725d..a4d23b0ebbc0 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -2970,24 +2970,27 @@ static void cfi_cleanup(struct module *mod)
 }
 
 /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
-char *module_flags(struct module *mod, char *buf)
+char *module_flags(struct module *mod, char *buf, bool show_state)
 {
 	int bx = 0;
 
 	BUG_ON(mod->state == MODULE_STATE_UNFORMED);
+	if (!mod->taints && !show_state)
+		goto out;
 	if (mod->taints ||
 	    mod->state == MODULE_STATE_GOING ||
 	    mod->state == MODULE_STATE_COMING) {
 		buf[bx++] = '(';
 		bx += module_flags_taint(mod->taints, buf + bx);
 		/* Show a - for module-is-being-unloaded */
-		if (mod->state == MODULE_STATE_GOING)
+		if (mod->state == MODULE_STATE_GOING && show_state)
 			buf[bx++] = '-';
 		/* Show a + for module-is-being-loaded */
-		if (mod->state == MODULE_STATE_COMING)
+		if (mod->state == MODULE_STATE_COMING && show_state)
 			buf[bx++] = '+';
 		buf[bx++] = ')';
 	}
+out:
 	buf[bx] = '\0';
 
 	return buf;
@@ -3120,7 +3123,7 @@ void print_modules(void)
 	list_for_each_entry_rcu(mod, &modules, list) {
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		pr_cont(" %s%s", mod->name, module_flags(mod, buf));
+		pr_cont(" %s%s", mod->name, module_flags(mod, buf, true));
 	}
 
 	print_unloaded_tainted_modules();
diff --git a/kernel/module/procfs.c b/kernel/module/procfs.c
index 9a8f4f0f6329..cf5b9f1e6ec4 100644
--- a/kernel/module/procfs.c
+++ b/kernel/module/procfs.c
@@ -91,7 +91,7 @@ static int m_show(struct seq_file *m, void *p)
 
 	/* Taints info */
 	if (mod->taints)
-		seq_printf(m, " %s", module_flags(mod, buf));
+		seq_printf(m, " %s", module_flags(mod, buf, true));
 
 	seq_puts(m, "\n");
 	return 0;
-- 
2.34.3