* Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote: > 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 This check is performed at mapping setup time in lib_ring_buffer_mmap_buf() already, so we can safely remove this duplicata. Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> --- .../lttng/lib/ringbuffer/ring_buffer_mmap.c | 3 --- 1 files changed, 0 insertions(+), 3 deletions(-) diff --git a/drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c b/drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c index 68221ee..cf37434 100644 --- a/drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c +++ b/drivers/staging/lttng/lib/ringbuffer/ring_buffer_mmap.c @@ -30,9 +30,6 @@ static int lib_ring_buffer_fault(struct vm_area_struct *vma, struct vm_fault *vm void **virt; unsigned long offset, sb_bindex; - if (!buf) - return VM_FAULT_OOM; - /* * Verify that faults are only done on the range of pages owned by the * reader. -- 1.7.5.4 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
