Re: [PATCH] printk: ringbuffer: Wrong data pointer when appending small string

On 2020-10-15, Sergey Senozhatsky sergey.senozhatsky@gmail.com wrote:

...

diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index 2493348a1631..24a960a89aa8 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -1125,7 +1125,10 @@ static char *data_realloc(struct printk_ringbuffer *rb, /* If the data block does not increase, there is nothing to do. */ if (head_lpos - next_lpos < DATA_SIZE(data_ring)) {

• blk = to_block(data_ring, blk_lpos->begin);
  

• if (wrapped)
  

• 	blk = to_block(data_ring, 0);
  

• else
  

• 	blk = to_block(data_ring, blk_lpos->begin);
  

  return &blk->data[0]; }

Great catch.

Indeed. I don't know how we missed that one. :-/

Reviewed-by: John Ogness john.ogness@linutronix.de