On 29/10/11 10:58, Julia Lawall wrote:

quoted

From: Julia Lawall <redacted>

Delete di->name from the error reporting code, as it is meaningless if di
is NULL.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression E, E1;
identifier f;
statement S1,S2,S3;
@@

if (E == NULL)
{
  ... when != if (E == NULL || ...) S1 else S2
      when != E = E1
*E->f
  ... when any
  return ...;
}
else S3
// </smpl>

Signed-off-by: Julia Lawall <redacted>

---
 drivers/net/wireless/brcm80211/brcmsmac/dma.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/brcm80211/brcmsmac/dma.c b/drivers/net/wireless/brcm80211/brcmsmac/dma.c
index b56a302..1d66f53 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/dma.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/dma.c

@@ -361,7 +361,7 @@ static uint _dma_ctrlflags(struct dma_info *di, uint mask, uint flags)
 	uint dmactrlflags = di->dma.dmactrlflags;

If di is null, we've already failed as it's dereferenced here.

quoted

 	if (di == NULL) {
-		DMA_ERROR(("%s: _dma_ctrlflags: NULL dma handle\n", di->name));
+		DMA_ERROR(("_dma_ctrlflags: NULL dma handle\n"));
 		return 0;
 	}

So, a better patch would be something like this:

(apologies if this doesn't apply - I've pretty much built it manually)

---

Though it's unlikely, di may be null, so we can't dereference
di->dma.dmactrlflags until we've checked it.

Move this de-reference after the check, and adjust the error
message to not require de-referencing di.

This is based upon Julia's original patch:
[ref]

Reported-by: Julia Lawall <redacted>
Signed-off-by: Julian Calaby <redacted>
CC: Julia Lawall <redacted>

diff --git a/drivers/net/wireless/brcm80211/brcmsmac/dma.c b/drivers/net/wireless/brcm80211/brcmsmac/dma.c
index b56a302..6ebec8f 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/dma.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/dma.c

@@ -358,13 +358,14 @@ static uint nrxdactive(struct dma_info *di, uint h, uint t
 
 static uint _dma_ctrlflags(struct dma_info *di, uint mask, uint flags)
 {
-       uint dmactrlflags = di->dma.dmactrlflags;
+       uint dmactrlflags;
 
        if (di == NULL) {
-               DMA_ERROR(("%s: _dma_ctrlflags: NULL dma handle\n", di->name));
+               DMA_ERROR(("_dma_ctrlflags: NULL dma handle\n"));
                return 0;
        }
 
+       dmactrlflags = di->dma.dmactrlflags;
        dmactrlflags &= ~mask;
        dmactrlflags |= flags;