Browse Source

gcc-4.6: printk: use stable variable to dump kmsg buffer

kmsg_dump takes care to sample the global variables
inside a spinlock, but then goes on to use the same
variables outside the spinlock region too.

Use the correct variable. This will make the race
window smaller.

Found by gcc 4.6's new warnings.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andi Kleen 15 năm trước cách đây
mục cha
commit
8c4af38e9b
1 tập tin đã thay đổi với 5 bổ sung5 xóa
  1. 5 5
      kernel/printk.c

+ 5 - 5
kernel/printk.c

@@ -1549,9 +1549,9 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 	chars = logged_chars;
 	spin_unlock_irqrestore(&logbuf_lock, flags);
 
-	if (logged_chars > end) {
-		s1 = log_buf + log_buf_len - logged_chars + end;
-		l1 = logged_chars - end;
+	if (chars > end) {
+		s1 = log_buf + log_buf_len - chars + end;
+		l1 = chars - end;
 
 		s2 = log_buf;
 		l2 = end;
@@ -1559,8 +1559,8 @@ void kmsg_dump(enum kmsg_dump_reason reason)
 		s1 = "";
 		l1 = 0;
 
-		s2 = log_buf + end - logged_chars;
-		l2 = logged_chars;
+		s2 = log_buf + end - chars;
+		l2 = chars;
 	}
 
 	if (!spin_trylock_irqsave(&dump_list_lock, flags)) {