On Thu, 11 Aug 2005, Steven Rostedt wrote: > > Found the problem. It is a bug with mmap_kmem. The order of checks is > wrong, so here's the patch. > - if (!pfn_valid(vma->vm_pgoff)) > - return -EIO; > val = (u64)vma->vm_pgoff << PAGE_SHIFT; > vma->vm_pgoff = __pa(val) >> PAGE_SHIFT; > + if (!pfn_valid(vma->vm_pgoff)) > + return -EIO; > return mmap_mem(file, vma);
Good find, looks right to me, so far as it goes (why does this check pfn_valid just on the first? and remap_pfn_range will not behave as you'd expect on most of kmem, not before Nick kills PageReserved; and there's the red-penned issue of vmalloc'ed areas too). Perhaps you're the first to mmap /dev/kmem: before those 2.6.11 changes, going back beyond 2.4.0, it seems to have expected to caller to subtract PAGE_OFFSET from the virtual address to give the file offset (when doing mmap, but not when doing read/write - senseless, especially given the variable behaviour of lseek to negative offset before the read/write). Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
