On Tue, Oct 09, 2001 at 04:23:49PM -0500, Shuanglin Wang wrote:
> I tried to use the pci_alloc_consistent() to allocate one-page DMA'able
> memory for my device driver. But, when booting up the system, it was
> always failed to execute the pci_alloc_consistent() by showing some
> memory errors.
> I traced the code to the function __alloc_page() in the file
> mm/page_alloc.c, and found the system called "wakeup_kswapd()". But at
> that time, the kswapd process pointer is a NULL pointer and the
> wakeup-related codes don't check the pointer is NULL or not, so the
> system was stopped because of dereferencing the null pointer.
This sounds like either memory corruption has overwritten the kernel pointer
or you're trying to use pci_alloc_consistent before the memory managment
> Anybody has some ideas about the problem? Or are there other convenient
> methods to allocate DMA'able memory?
Anything else than the pci_alloc_* functions isn't portable.