• Jiri Slaby's avatar
    x86: crash_dump: Fix non-pae kdump kernel memory accesses · 72ed7de7
    Jiri Slaby authored
    Non-PAE 32-bit dump kernels may wrap an address around 4G and
    poke unwanted space. ptes there are 32-bit long, and since
    pfn << PAGE_SIZE may exceed this limit, high pfn bits are
    cropped and wrong address mapped by kmap_atomic_pfn in
    copy_oldmem_page.
    
    Don't allow this behavior in non-PAE kdump kernels by checking
    pfns passed into copy_oldmem_page. In the case of failure,
    userspace process gets EFAULT.
    
    [v2]
    - fix comments
    - move ifdefs inside the function
    Signed-off-by: default avatarJiri Slaby <jirislaby@gmail.com>
    Cc: Vivek Goyal <vgoyal@redhat.com>
    Cc: Eric W. Biederman <ebiederm@xmission.com>
    Cc: Simon Horman <horms@verge.net.au>
    Cc: Paul Mundt <lethal@linux-sh.org>
    LKML-Reference: <1256551903-30567-1-git-send-email-jirislaby@gmail.com>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    72ed7de7
crash_dump_32.c 2.6 KB