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authorJohn Ogness <john.ogness@linutronix.de>2021-01-13 15:48:34 +0106
committerPetr Mladek <pmladek@suse.com>2021-01-15 11:30:03 +0100
commit668af87f995b6d6d09595c088ad1fb5dd9ff25d2 (patch)
tree45dd411f4de2f3e058c5349ea06ffccf3d121308 /kernel/printk
parentb031a684bfd01d633c79d281bd0cf11c2f834ada (diff)
printk: ringbuffer: fix line counting
Counting text lines in a record simply involves counting the number of newline characters (+1). However, it is searching the full data block for newline characters, even though the text data can be (and often is) a subset of that area. Since the extra area in the data block was never initialized, the result is that extra newlines may be seen and counted. Restrict newline searching to the text data length. Fixes: b6cf8b3f3312 ("printk: add lockless ringbuffer") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210113144234.6545-1-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk')
-rw-r--r--kernel/printk/printk_ringbuffer.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c
index 74e25a1704f2..617dd6358965 100644
--- a/kernel/printk/printk_ringbuffer.c
+++ b/kernel/printk/printk_ringbuffer.c
@@ -1720,7 +1720,7 @@ static bool copy_data(struct prb_data_ring *data_ring,
/* Caller interested in the line count? */
if (line_count)
- *line_count = count_lines(data, data_size);
+ *line_count = count_lines(data, len);
/* Caller interested in the data content? */
if (!buf || !buf_size)