• Dave Jones's avatar
    [PATCH] Fix cpufreq vs hotplug lockdep recursion. · a496e25d
    Dave Jones authored
    [ There's some not quite baked bits in cpufreq-git right now
      so sending this on as a patch instead ]
    
    On Thu, 2006-07-06 at 07:58 -0700, Tom London wrote:
    
    > After installing .2356 I get this each time I boot:
    > =======================================================
    > [ INFO: possible circular locking dependency detected ]
    > -------------------------------------------------------
    > S06cpuspeed/1620 is trying to acquire lock:
    >  (dbs_mutex){--..}, at: [<c060d6bb>] mutex_lock+0x21/0x24
    >
    > but task is already holding lock:
    >  (cpucontrol){--..}, at: [<c060d6bb>] mutex_lock+0x21/0x24
    >
    > which lock already depends on the new lock.
    >
    
    make sure the cpu hotplug recursive mutex (yuck) is taken early in the
    cpufreq codepaths to avoid a AB-BA deadlock.
    Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
    Signed-off-by: default avatarDave Jones <davej@redhat.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    a496e25d
cpufreq.c 42 KB