From: Jiri Kosina <jikos@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Petr Mladek <pmladek@suse.com>, Miroslav Benes <mbenes@suse.cz>,
Jessica Yu <jeyu@kernel.org>,
Joe Lawrence <joe.lawrence@redhat.com>,
linux-kernel@vger.kernel.org, live-patching@vger.kernel.org,
Johannes Erdfelt <johannes@erdfelt.com>,
Ingo Molnar <mingo@kernel.org>,
mhiramat@kernel.org, torvalds@linux-foundation.org
Subject: [PATCH] ftrace/x86: anotate text_mutex split between ftrace_arch_code_modify_post_process() and ftrace_arch_code_modify_prepare()
Date: Sat, 29 Jun 2019 23:22:33 +0200 (CEST) [thread overview]
Message-ID: <nycvar.YFH.7.76.1906292321170.27227@cbobk.fhfr.pm> (raw)
In-Reply-To: <20190629171931.770f05a5@gandalf.local.home>
From: Jiri Kosina <jkosina@suse.cz>
ftrace_arch_code_modify_prepare() is acquiring text_mutex, while the
corresponding release is happening in ftrace_arch_code_modify_post_process().
This has already been documented in the code, but let's also make the fact
that this is intentional clear to the semantic analysis tools such as sparse.
Fixes: 39611265edc1a ("ftrace/x86: Add a comment to why we take text_mutex in ftrace_arch_code_modify_prepare()")
Fixes: d5b844a2cf507 ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
arch/x86/kernel/ftrace.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index d7e93b2783fd..76228525acd0 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -35,6 +35,7 @@
#ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_arch_code_modify_prepare(void)
+ __acquires(&text_mutex)
{
/*
* Need to grab text_mutex to prevent a race from module loading
@@ -48,6 +49,7 @@ int ftrace_arch_code_modify_prepare(void)
}
int ftrace_arch_code_modify_post_process(void)
+ __releases(&text_mutex)
{
set_all_modules_text_ro();
set_kernel_text_ro();
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2019-06-29 21:22 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 8:13 [PATCH] ftrace: Remove possible deadlock between register_kprobe() and ftrace_run_update_code() Petr Mladek
2019-06-27 22:17 ` Thomas Gleixner
2019-06-27 22:47 ` Josh Poimboeuf
2019-06-27 23:04 ` Steven Rostedt
2019-06-27 23:09 ` Thomas Gleixner
2019-06-27 23:12 ` Steven Rostedt
2019-06-27 23:19 ` Josh Poimboeuf
2019-06-27 23:25 ` Thomas Gleixner
2019-06-27 23:25 ` Steven Rostedt
2019-06-28 1:13 ` Steven Rostedt
2019-06-28 1:17 ` Josh Poimboeuf
2019-06-28 17:33 ` Jiri Kosina
2019-06-28 17:37 ` Steven Rostedt
2019-06-29 20:56 ` Jiri Kosina
2019-06-29 21:19 ` Steven Rostedt
2019-06-29 21:22 ` Jiri Kosina [this message]
2019-06-28 7:32 ` Miroslav Benes
2019-06-28 10:52 ` Petr Mladek
2019-06-28 13:54 ` Steven Rostedt
2019-06-28 15:46 ` Steven Rostedt
2019-06-28 15:51 ` Josh Poimboeuf
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