[lkml]   [2011]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 1/3] comm: Introduce comm_lock spinlock to protect task->comm access

    * John Stultz <> wrote:

    > The implicit rules for current->comm access being safe without locking are no
    > longer true. Accessing current->comm without holding the task lock may result
    > in null or incomplete strings (however, access won't run off the end of the
    > string).

    This is rather unfortunate - task->comm is used in a number of performance
    critical codepaths such as tracing.

    Why does this matter so much? A NULL string is not a big deal.

    Note, since task->comm is 16 bytes there's the CMPXCHG16B instruction on x86
    which could be used to update it atomically, should atomicity really be



     \ /
      Last update: 2011-05-17 23:31    [W:0.025 / U:104.048 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site