[PATCH 3/5] printk: Add comment about tricky check for text buffer size

[Petr Mladek]

There is no check for potential "text_len" overflow. It is not needed
because only valid level is detected. It took me some time to understand why.
It would deserve a comment ;-)

Signed-off-by: Petr Mladek <pmladek@xxxxxxx>
---
 kernel/printk/printk.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 54a4439d021c..bc6eed48a454 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1562,6 +1562,11 @@ asmlinkage int vprintk_emit(int facility, int level,
 			case 'd':	/* KERN_DEFAULT */
 				lflags |= LOG_PREFIX;
 			}
+			/*
+			 * No need to check length here because vscnprintf
+			 * put '\0' at the end of the string. Only valid and
+			 * newly printed level is detected.
+			 */
 			text_len -= end_of_header - text;
 			text = (char *)end_of_header;
 		}
-- 
1.8.4

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