• Borislav Petkov's avatar
    x86, hotplug: Serialize CPU hotplug to avoid bringup concurrency issues · d7c53c9e
    Borislav Petkov authored
    When testing cpu hotplug code on 32-bit we kept hitting the "CPU%d:
    Stuck ??" message due to multiple cores concurrently accessing the
    cpu_callin_mask, among others.
    
    Since these codepaths are not protected from concurrent access due to
    the fact that there's no sane reason for making an already complex
    code unnecessarily more complex - we hit the issue only when insanely
    switching cores off- and online - serialize hotplugging cores on the
    sysfs level and be done with it.
    
    [ v2.1: fix !HOTPLUG_CPU build ]
    
    Cc: <stable@kernel.org>
    Signed-off-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
    LKML-Reference: <20100819181029.GC17171@aftab>
    Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
    d7c53c9e
smpboot.c 34.2 KB