linux-kernel - [RFC PATCH v4 06/22] init/main.c: Alloc initcall_command_line in do

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Message-Id: <157528166664.22451.16147144831500689849.stgit@devnote2>
Date:   Mon,  2 Dec 2019 19:14:26 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Steven Rostedt <rostedt@...dmis.org>,
        Frank Rowand <frowand.list@...il.com>
Cc:     Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Tim Bird <Tim.Bird@...y.com>, Jiri Olsa <jolsa@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Rob Herring <robh+dt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Jonathan Corbet <corbet@....net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-doc@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [RFC PATCH v4 06/22] init/main.c: Alloc initcall_command_line in do_initcall() and free it

Since initcall_command_line is used as a temporary buffer,
it could be freed after usage. Allocate it in do_initcall()
and free it after used.

Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 init/main.c |   26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/init/main.c b/init/main.c
index 27f70fa37b18..b6fd906e7714 100644
--- a/init/main.c
+++ b/init/main.c
@@ -137,8 +137,6 @@ char __initdata boot_command_line[COMMAND_LINE_SIZE];
 char *saved_command_line;
 /* Command line for parameter parsing */
 static char *static_command_line;
-/* Command line for per-initcall parameter parsing */
-static char *initcall_command_line;
 
 static char *execute_command;
 static char *ramdisk_execute_command;
@@ -433,10 +431,6 @@ static void __init setup_command_line(char *command_line)
 	if (!saved_command_line)
 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
 
-	initcall_command_line =	memblock_alloc(len, SMP_CACHE_BYTES);
-	if (!initcall_command_line)
-		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
-
 	static_command_line = memblock_alloc(len, SMP_CACHE_BYTES);
 	if (!static_command_line)
 		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
@@ -1044,13 +1038,12 @@ static const char *initcall_level_names[] __initdata = {
 	"late",
 };
 
-static void __init do_initcall_level(int level)
+static void __init do_initcall_level(int level, char *command_line)
 {
 	initcall_entry_t *fn;
 
-	strcpy(initcall_command_line, saved_command_line);
 	parse_args(initcall_level_names[level],
-		   initcall_command_line, __start___param,
+		   command_line, __start___param,
 		   __stop___param - __start___param,
 		   level, level,
 		   NULL, &repair_env_string);
@@ -1063,9 +1056,20 @@ static void __init do_initcall_level(int level)
 static void __init do_initcalls(void)
 {
 	int level;
+	size_t len = strlen(saved_command_line) + 1;
+	char *command_line;
+
+	command_line = kzalloc(len, GFP_KERNEL);
+	if (!command_line)
+		panic("%s: Failed to allocate %zu bytes\n", __func__, len);
+
+	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) {
+		/* Parser modifies command_line, restore it each time */
+		strcpy(command_line, saved_command_line);
+		do_initcall_level(level, command_line);
+	}
 
-	for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++)
-		do_initcall_level(level);
+	kfree(command_line);
 }
 
 /*