Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit eeb34e21 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Greg Kroah-Hartman
Browse files

lttng lib: ring buffer move null pointer check to open 



* Dan Carpenter <dan.carpenter@oracle.com> wrote:
> The patch c844b2f5: "lttng lib: ring buffer" from Nov 28, 2011,
> leads to the following Smatch complaint:
>
> drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c +86
> +lib_ring_buffer_mmap_buf()
>          warn: variable dereferenced before check 'buf' (see line 79)
>
> drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c
>     78          unsigned long length = vma->vm_end - vma->vm_start;
>     79          struct channel *chan = buf->backend.chan;
>                                        ^^^^^^^^^^^^^^^^^
> Dereference.
>
>     80          const struct lib_ring_buffer_config *config = chan->backend.config;
>     81          unsigned long mmap_buf_len;
>     82
>     83          if (config->output != RING_BUFFER_MMAP)
>     84                  return -EINVAL;
>     85
>     86          if (!buf)
>                     ^^^^
> Check.
>
>     87                  return -EBADF;
>     88

Let's move the NULL buf check to the file "open", where it belongs. The
"open" file operation is the actual interface between lib ring buffer
and the modules using it.

Reported-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e5f77873

drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c

+0 −3
Original line number Diff line number Diff line
@@ -80,9 +80,6 @@ static int lib_ring_buffer_mmap_buf(struct lib_ring_buffer *buf, 
	if (config->output != RING_BUFFER_MMAP)

		return -EINVAL;



	if (!buf)

		return -EBADF;



	mmap_buf_len = chan->backend.buf_size;

	if (chan->backend.extra_reader_sb)

		mmap_buf_len += chan->backend.subbuf_size;

drivers/staging/lttng/lib/ringbuffer/ring_buffer_vfs.c

+3 −0
Original line number Diff line number Diff line
@@ -42,6 +42,9 @@ int lib_ring_buffer_open(struct inode *inode, struct file *file) 
	struct lib_ring_buffer *buf = inode->i_private;

	int ret;



	if (!buf)

		return -EINVAL;



	ret = lib_ring_buffer_open_read(buf);

	if (ret)

		return ret;