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ftrace/x86: Anotate text_mutex split between ftrace_arch_code_modify_post_process() and ftrace_arch_code_modify_prepare()

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commit 074376ac0e upstream.

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.

Link: http://lkml.kernel.org/r/nycvar.YFH.7.76.1906292321170.27227@cbobk.fhfr.pm

Fixes: 39611265ed ("ftrace/x86: Add a comment to why we take text_mutex in ftrace_arch_code_modify_prepare()")
Fixes: d5b844a2cf ("ftrace/x86: Remove possible deadlock between register_kprobe() and ftrace_run_update_code()")
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiri Kosina 2019-06-29 23:22:33 +02:00 • committed by Greg Kroah-Hartman
commit cde88c24f9
1 changed files with 2 additions and 0 deletions
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2
arch/x86/kernel/ftrace.c
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@ -35,6 +35,7 @@
#ifdef CONFIG_DYNAMIC_FTRACE
int ftrace_arch_code_modify_prepare(void)
__acquires(&text_mutex)
{
mutex_lock(&text_mutex);
set_kernel_text_rw();
@ -43,6 +44,7 @@ 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();