[lkml]   [2008]   [Nov]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH] kprobes: bugfix: try_module_get even if calling_mod is NULL
    On Fri, 07 Nov 2008 11:28:02 +0900 Masami Hiramatsu <> wrote:

    > Andrew Morton wrote:
    > > I do not understand this description "Get probed module even if the
    > > caller is in the kernel core code".
    > >
    > > What bug is being fixed here? What is the kernel behaviour before and
    > > after the patch?
    > When someone called register_*probe() from kernel-core code(not from
    > module) and that probes a kernel module, users can remove the probed
    > module because kprobe doesn't increment reference counter of the module.
    > (on the other hand, if the kernel-module calls register_*probe,
    > kprobe increments refcount of the probed module.)
    > Currently, we have no register_*probe() calling from kernel-core(except
    > smoke-test, but the smoke-test doesn't probe module), so there is no
    > real bugs. But the logic is wrong(or not fair) and it can causes a
    > problem when someone might want to probe module from kernel.
    > After this patch is applied, even if someone put register_*probe() call
    > in the kernel-core code, it increments the reference counter of the
    > probed module, and it prevents user to remove the module until stopping
    > probing it.
    > > Was the bug present in 2.6.27, 2.6.26 etc? Or was it a post-2.6.28
    > > regression?
    > Hmm, it might be an enhancement, because currently the kernel doesn't
    > have real bugs.

    OK, thanks, so I scheduled this for 2.6.29.

    Also, I decided that
    is needed in 2.6.28. Please let me know if that was incorrect. Please
    also let me know if you think that patch is needed in 2.6.27.x or

     \ /
      Last update: 2008-11-07 03:59    [W:0.021 / U:14.012 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site