On Tue, 29 Apr 2014 11:53:10 +0900 Daeseok Youn <daeseok.youn@xxxxxxxxx> wrote: > "dev" cannot be NULL because it is already checked before > calling dma_pool_create(). > > Signed-off-by: Daeseok Youn <daeseok.youn@xxxxxxxxx> > --- > If dev can be NULL, it has NULL deferencing when kmalloc_node() > is called after enabling CONFIG_NUMA. hm, this is unclear. The code which handles the dev==NULL case was obviously put there deliberately, presumably with the intention of permitting drivers to call dma_pool_create() without a device*. This code is very old. A lot of drivers call dma_pool_create() (I doubt if you audited all of them!) and perhaps there are some which use this feature and have never been run on NUMA hardware. I think I'll apply the patch anyway because such drivers (if they exist) probably need some attending to. I rewrote the changelog thusly: : "dev" cannot be NULL because it is already checked before calling : dma_pool_create(). : : If dev ever was NULL, the code would oops in dev_to_node() after enabling : CONFIG_NUMA. : : It is possible that some driver is using dev==NULL and has never been run : on a NUMA machine. Such a driver is probably outdated, possibly buggy and : will need some attention if it starts triggering NULL derefs. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>