[PATCH v5 4/4] printk: Give error on attempt to set log buffer length to over 4G

[zhe.he]

From: He Zhe <zhe...@windriver.com>

Give explicit error for users who want to use larger log buffer.

Signed-off-by: He Zhe <zhe...@windriver.com>
Cc: pmla...@suse.com
Cc: sergey.senozhat...@gmail.com
Cc: rost...@goodmis.org
---
 kernel/printk/printk.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index b84aac0..5ccfd5d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1039,18 +1039,23 @@ void log_buf_vmcoreinfo_setup(void)
 static unsigned long __initdata new_log_buf_len;
 
 /* we practice scaling the ring buffer by powers of 2 */
-static void __init log_buf_len_update(unsigned size)
+static void __init log_buf_len_update(u64 size)
 {
+       if (size > UINT_MAX) {
+               size = UINT_MAX;
+               pr_err("log_buf over 4G is not supported.\n");
+       }
+
        if (size)
                size = roundup_pow_of_two(size);
        if (size > log_buf_len)
-               new_log_buf_len = size;
+               new_log_buf_len = (unsigned long)size;
 }
 
 /* save requested log_buf_len since it's too early to process it */
 static int __init log_buf_len_setup(char *str)
 {
-       unsigned int size;
+       u64 size;
 
        if (!str)
                return -EINVAL;
-- 
2.7.4