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From: Christoph Hellwig <hch@lst.de>
To: Frederic Barrat <fbarrat@linux.ibm.com>,
	Andrew Donnellan <ajd@linux.ibm.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Jessica Yu <jeyu@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
	Petr Mladek <pmladek@suse.com>,
	Joe Lawrence <joe.lawrence@redhat.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>,
	Michal Marek <michal.lkml@markovi.net>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	dri-devel@lists.freedesktop.org, live-patching@vger.kernel.org,
	linux-kbuild@vger.kernel.org
Subject: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
Date: Tue,  2 Feb 2021 13:13:26 +0100	[thread overview]
Message-ID: <20210202121334.1361503-6-hch@lst.de> (raw)
In-Reply-To: <20210202121334.1361503-1-hch@lst.de>

Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.  Note that this slightly changes the
behavior for the livepatch code in that the symbols from vmlinux are not
iterated anymore if objname is set, but that actually is the desired
behavior in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
 kernel/kallsyms.c       |  6 +++++-
 kernel/livepatch/core.c |  2 --
 kernel/module.c         | 13 ++++---------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 262cd9b003b9f0..335d988bd81117 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -164,12 +164,10 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
 		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 6772fb2680eb3e..25345792c770d1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -255,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -4379,8 +4374,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4396,10 +4390,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2


WARNING: multiple messages have this Message-ID
From: Christoph Hellwig <hch@lst.de>
To: Frederic Barrat <fbarrat@linux.ibm.com>,
	Andrew Donnellan <ajd@linux.ibm.com>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Jessica Yu <jeyu@kernel.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
	Petr Mladek <pmladek@suse.com>,
	Joe Lawrence <joe.lawrence@redhat.com>
Cc: Michal Marek <michal.lkml@markovi.net>,
	linux-kbuild@vger.kernel.org,
	Masahiro Yamada <masahiroy@kernel.org>,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	live-patching@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol
Date: Tue,  2 Feb 2021 13:13:26 +0100	[thread overview]
Message-ID: <20210202121334.1361503-6-hch@lst.de> (raw)
In-Reply-To: <20210202121334.1361503-1-hch@lst.de>

Require an explicit call to module_kallsyms_on_each_symbol to look
for symbols in modules instead of the call from kallsyms_on_each_symbol,
and acquire module_mutex inside of module_kallsyms_on_each_symbol instead
of leaving that up to the caller.  Note that this slightly changes the
behavior for the livepatch code in that the symbols from vmlinux are not
iterated anymore if objname is set, but that actually is the desired
behavior in this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Miroslav Benes <mbenes@suse.cz>
---
 kernel/kallsyms.c       |  6 +++++-
 kernel/livepatch/core.c |  2 --
 kernel/module.c         | 13 ++++---------
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index fe9de067771c34..a0d3f0865916f9 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -177,6 +177,10 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,7 +196,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
 
 static unsigned long get_symbol_pos(unsigned long addr,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 262cd9b003b9f0..335d988bd81117 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -164,12 +164,10 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
 		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;
diff --git a/kernel/module.c b/kernel/module.c
index 6772fb2680eb3e..25345792c770d1 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -255,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -4379,8 +4374,7 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
-	module_assert_mutex();
-
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4396,10 +4390,11 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
 #endif /* CONFIG_KALLSYMS */
 
-- 
2.29.2


  parent reply	other threads:[~2021-02-02 12:15 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-02 12:13 module loader dead code removal and cleanups v3 Christoph Hellwig
2021-02-02 12:13 ` [PATCH 01/13] powerpc/powernv: remove get_cxl_module Christoph Hellwig
2021-02-04 10:44   ` Michael Ellerman
2021-02-02 12:13 ` [PATCH 02/13] drm: remove drm_fb_helper_modinit Christoph Hellwig
2021-02-02 12:13 ` [PATCH 03/13] module: unexport find_module and module_mutex Christoph Hellwig
2021-02-02 12:13 ` [PATCH 04/13] module: use RCU to synchronize find_module Christoph Hellwig
2021-02-02 12:13 ` Christoph Hellwig [this message]
2021-02-03  8:58   ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Petr Mladek
2021-02-02 12:13 ` [PATCH 06/13] kallsyms: only build {, module_}kallsyms_on_each_symbol when required Christoph Hellwig
2021-02-02 14:03   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 07/13] module: mark module_mutex static Christoph Hellwig
2021-02-02 14:04   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 08/13] module: remove each_symbol_in_section Christoph Hellwig
2021-02-02 14:04   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 09/13] module: merge each_symbol_section into find_symbol Christoph Hellwig
2021-02-02 14:04   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 10/13] module: pass struct find_symbol_args to find_symbol Christoph Hellwig
2021-02-02 14:07   ` Miroslav Benes
2021-02-02 15:41     ` Christoph Hellwig
2021-02-03  9:04     ` Christoph Hellwig
2021-02-03  9:31       ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 11/13] module: move struct symsearch to module.c Christoph Hellwig
2021-02-02 14:10   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 12/13] module: remove EXPORT_SYMBOL_GPL_FUTURE Christoph Hellwig
2021-02-02 14:12   ` Miroslav Benes
2021-02-02 12:13 ` [PATCH 13/13] module: remove EXPORT_UNUSED_SYMBOL* Christoph Hellwig
2021-02-02 14:21   ` Miroslav Benes
2021-02-02 14:37 ` module loader dead code removal and cleanups v3 Jessica Yu
2021-02-02 15:23   ` Christoph Hellwig
2021-02-02 17:38   ` Emil Velikov
2021-02-08 11:36 ` Jessica Yu
  -- strict thread matches above, loose matches on Subject: below --
2021-01-28 18:14 module loader dead code removal and cleanups v2 Christoph Hellwig
2021-01-28 18:14 ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Christoph Hellwig
2021-01-29  9:43   ` Petr Mladek
2021-02-01 11:47     ` Christoph Hellwig
2021-02-01 13:37       ` Miroslav Benes
2021-02-01 16:28         ` Christoph Hellwig
2021-02-02 10:45           ` Miroslav Benes
2021-02-01 14:02   ` Miroslav Benes
2021-01-21  7:49 module loader dead code removal and cleanusp Christoph Hellwig
2021-01-21  7:49 ` [PATCH 05/13] kallsyms: refactor {,module_}kallsyms_on_each_symbol Christoph Hellwig

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