• Vijay Balakrishna's avatar
    kdump: append kernel build-id string to VMCOREINFO · 0935288c
    Vijay Balakrishna authored
    Make kernel GNU build-id available in VMCOREINFO.  Having build-id in
    VMCOREINFO facilitates presenting appropriate kernel namelist image with
    debug information file to kernel crash dump analysis tools.  Currently
    VMCOREINFO lacks uniquely identifiable key for crash analysis automation.
    
    Regarding if this patch is necessary or matching of linux_banner and
    OSRELEASE in VMCOREINFO employed by crash(8) meets the need -- IMO,
    build-id approach more foolproof, in most instances it is a cryptographic
    hash generated using internal code/ELF bits unlike kernel version string
    upon which linux_banner is based that is external to the code.  I feel
    each is intended for a different purpose.  Also OSRELEASE is not suitable
    when two different kernel builds from same version with different features
    enabled.
    
    Currently for most linux (and non-linux) systems build-id can be extracted
    using standard methods for file types such as user mode crash dumps,
    shared libraries, loadable kernel modules etc., This is an exception for
    linux kernel dump.  Having build-id in VMCOREINFO brings some uniformity
    for automation tools.
    
    Tyler said:
    
    : I think this is a nice improvement over today's linux_banner approach for
    : correlating vmlinux to a kernel dump.
    :
    : The elf notes parsing in this patch lines up with what is described in in
    : the "Notes (Nhdr)" section of the elf(5) man page.
    :
    : BUILD_ID_MAX is sufficient to hold a sha1 build-id, which is the default
    : build-id type today in GNU ld(2).  It is also sufficient to hold the
    : "fast" build-id, which is the default build-id type today in LLVM lld(2).
    Signed-off-by: default avatarVijay Balakrishna <vijayb@linux.microsoft.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Reviewed-by: default avatarTyler Hicks <tyhicks@linux.microsoft.com>
    Acked-by: default avatarBaoquan He <bhe@redhat.com>
    Cc: Dave Young <dyoung@redhat.com>
    Cc: Vivek Goyal <vgoyal@redhat.com>
    Link: http://lkml.kernel.org/r/1591849672-34104-1-git-send-email-vijayb@linux.microsoft.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    0935288c
crash_core.c 12.8 KB