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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Daniel Gomez <da.gomez@samsung.com>,
	Luis Chamberlain <mcgrof@kernel.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Petr Pavlu <petr.pavlu@suse.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH v2 07/28] module: Use RCU in __find_kallsyms_symbol_value().
Date: Fri, 20 Dec 2024 18:41:21 +0100	[thread overview]
Message-ID: <20241220174731.514432-8-bigeasy@linutronix.de> (raw)
In-Reply-To: <20241220174731.514432-1-bigeasy@linutronix.de>

module::kallsyms can be accessed under RCU assumption.

Use rcu_dereference() to access module::kallsyms.
Update callers.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 kernel/module/kallsyms.c | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/kernel/module/kallsyms.c b/kernel/module/kallsyms.c
index 3cba9f933b24f..e3c55bc879c11 100644
--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -407,7 +407,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 static unsigned long __find_kallsyms_symbol_value(struct module *mod, const char *name)
 {
 	unsigned int i;
-	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
+	struct mod_kallsyms *kallsyms = rcu_dereference(mod->kallsyms);
 
 	for (i = 0; i < kallsyms->num_symtab; i++) {
 		const Elf_Sym *sym = &kallsyms->symtab[i];
@@ -447,24 +447,15 @@ static unsigned long __module_kallsyms_lookup_name(const char *name)
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name)
 {
-	unsigned long ret;
-
 	/* Don't lock: we're in enough trouble already. */
 	guard(rcu)();
-	preempt_disable();
-	ret = __module_kallsyms_lookup_name(name);
-	preempt_enable();
-	return ret;
+	return __module_kallsyms_lookup_name(name);
 }
 
 unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
 {
-	unsigned long ret;
-
-	preempt_disable();
-	ret = __find_kallsyms_symbol_value(mod, name);
-	preempt_enable();
-	return ret;
+	guard(rcu)();
+	return __find_kallsyms_symbol_value(mod, name);
 }
 
 int module_kallsyms_on_each_symbol(const char *modname,
-- 
2.45.2


  parent reply	other threads:[~2024-12-20 17:47 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-20 17:41 [PATCH v2 00/28] module: Use RCU instead of RCU-sched Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 01/28] module: Extend the preempt disabled section in dereference_symbol_descriptor() Sebastian Andrzej Siewior
2025-01-07 10:58   ` Sergey Senozhatsky
2024-12-20 17:41 ` [PATCH v2 02/28] module: Begin to move from RCU-sched to RCU Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 03/28] module: Use proper RCU assignment in add_kallsyms() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 04/28] module: Use RCU in find_kallsyms_symbol() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 05/28] module: Use RCU in module_get_kallsym() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 06/28] module: Use RCU in find_module_all() Sebastian Andrzej Siewior
2025-01-02 14:16   ` Petr Mladek
2024-12-20 17:41 ` Sebastian Andrzej Siewior [this message]
2024-12-20 17:41 ` [PATCH v2 08/28] module: Use RCU in module_kallsyms_on_each_symbol() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 09/28] module: Remove module_assert_mutex_or_preempt() from try_add_tainted_module() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 10/28] module: Use RCU in find_symbol() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 11/28] module: Use RCU in __is_module_percpu_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 12/28] module: Allow __module_address() to be called from RCU section Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 13/28] module: Use RCU in search_module_extables() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 14/28] module: Use RCU in all users of __module_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 15/28] module: Use RCU in all users of __module_text_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 16/28] ARM: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 17/28] arm64: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 18/28] LoongArch/orc: Use RCU in all users of __module_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 19/28] LoongArch: ftrace: Use RCU in all users of __module_text_address() Sebastian Andrzej Siewior
2024-12-27 17:19   ` Steven Rostedt
2025-01-07 17:12     ` Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 20/28] powerpc/ftrace: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 21/28] x86: Use RCU in all users of __module_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 22/28] jump_label: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 23/28] jump_label: Use RCU in all users of __module_text_address() Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 24/28] bpf: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 25/28] kprobes: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 26/28] static_call: " Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 27/28] bug: Use RCU instead RCU-sched to protect module_bug_list Sebastian Andrzej Siewior
2024-12-20 17:41 ` [PATCH v2 28/28] cfi: Use RCU while invoking __module_address() Sebastian Andrzej Siewior
2024-12-30 21:13   ` Petr Pavlu
2025-01-02 23:59     ` Sami Tolvanen
2024-12-31  3:33   ` Elliot Berman
2025-01-03  0:24     ` Sami Tolvanen
2025-01-06 18:00       ` Elliot Berman
2025-01-06 21:24         ` Sami Tolvanen
2025-01-07 15:44           ` Sebastian Andrzej Siewior
2025-01-02 12:47 ` [PATCH v2 00/28] module: Use RCU instead of RCU-sched Christophe Leroy
2025-01-07 15:45   ` Sebastian Andrzej Siewior
2025-01-07  8:48 ` Peter Zijlstra

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