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    SubjectRe: BUG: NULL pointer dereference at 00000000 -- IP: [<f8e783d5>] :b43:b43_dma_mapping_error+0x16/0x155
    Sorry, I forgot to label the kernel tree.  It is 2.6.26-rc5-mm2.

    On Tue, Jun 10, 2008 at 10:37 AM, Michael Buesch <mb@bu3sch.de> wrote:
    > On Tuesday 10 June 2008 16:34:21 Michael Buesch wrote:
    >> On Tuesday 10 June 2008 16:29:17 Vegard Nossum wrote:
    >> > On Tue, Jun 10, 2008 at 4:23 PM, Michael Buesch <mb@bu3sch.de> wrote:
    >> > > On Tuesday 10 June 2008 16:09:37 Miles Lane wrote:
    >> > >> BUG: unable to handle kernel NULL pointer dereference at 00000000
    >> > >> IP: [<f8e783d5>] :b43:b43_dma_mapping_error+0x16/0x155
    >> > >
    >> > >
    >> > > It seems to crash at
    >> > > 60 extern const struct dma_mapping_ops *dma_ops;
    >> > > 61
    >> > > 62 static inline int dma_mapping_error(dma_addr_t dma_addr)
    >> > > 63 {
    >> > > 64 if (dma_ops->mapping_error)
    >> > > 65 return dma_ops->mapping_error(dma_addr);
    >> > > 66
    >> > > 67 return (dma_addr == bad_dma_address);
    >> > > 68 }
    >> >
    >> > No, this is wrong.
    >> >
    >> > /* Check if a DMA mapping address is invalid. */
    >> > static bool b43_dma_mapping_error(struct b43_dmaring *ring,
    >> > dma_addr_t addr,
    >> > size_t buffersize, bool dma_to_device)
    >> > {
    >> > if (unlikely(dma_mapping_error(ring->dev->dev->dma_dev, addr)))
    >> >
    >> > It crashes on this line ---^
    >>
    >> Which calls dma_mapping_error(), correct?
    >>
    >> But you are right. I see the bug now.
    >> ring->dev is assigned after the call.
    >> I wonder why it works reliably on all of my machines.
    >>
    >
    > Ehm no wait a second...
    > What strange tree are you looking at?
    > This is a copy of the code from my local tree.
    >
    > 516 /* Check if a DMA mapping address is invalid. */
    > 517 static bool b43_dma_mapping_error(struct b43_dmaring *ring,
    > 518 dma_addr_t addr,
    > 519 size_t buffersize, bool dma_to_device)
    > 520 {
    > 521 if (unlikely(dma_mapping_error(addr)))
    > 522 return 1;
    >
    > This code is perfectly fine.
    > This must be some merge error in some upstream tree.
    >
    > --
    > Greetings Michael.
    >


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