From mboxrd@z Thu Jan  1 00:00:00 1970
From: dan.carpenter@oracle.com (Dan Carpenter)
Date: Wed, 30 Nov 2011 11:45:27 +0300
Subject: [lttng-dev] lttng lib: ring buffer
Message-ID: <20111130084527.GF6268@elgon.mountain>

Hello Mathieu Desnoyers,

This is a semi-automatic email about new static checker warnings.

The patch c844b2f5cfea: "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	

regards,
dan carpenter