[lttng-dev] lttng lib: ring buffer

Dan Carpenter dan.carpenter at oracle.com
Wed Nov 30 03:44:49 EST 2011


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 +33 lib_ring_buffer_fault()
	 warn: variable dereferenced before check 'buf' (see line 26)

drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c
    25		struct lib_ring_buffer *buf = vma->vm_private_data;
    26		struct channel *chan = buf->backend.chan;
                                       ^^^^^^^^^^^^^^^^^
Dereference.

    27		const struct lib_ring_buffer_config *config = chan->backend.config;
    28		pgoff_t pgoff = vmf->pgoff;
    29		struct page **page;
    30		void **virt;
    31		unsigned long offset, sb_bindex;
    32	
    33		if (!buf)
                    ^^^^
Check.

    34			return VM_FAULT_OOM;
    35	

regards,
dan carpenter




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