lkml.org 
[lkml]   [2015]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Subjectmodule: fix module_refcount() return when running in a module exit routine
    From
    Date
    From: James Bottomley <JBottomley@Parallels.com>

    After e513cc1 module: Remove stop_machine from module unloading,
    module_refcount() is returning (unsigned long)-1 when called from within
    a routine that runs in module_exit. This is confusing the scsi device
    put code which is coded to detect a module_refcount() of zero for
    running within a module exit routine and not try to do another
    module_put. The fix is to restore the original behaviour of
    module_refcount() and return zero if we're running inside an exit
    routine.

    Fixes: e513cc1c07e2ab93a4514eec9833e031df3e30bb
    Reported-by: Bart Van Assche <bvanassche@acm.org>
    Signed-off-by: James Bottomley <JBottomley@Parallels.com>

    ---

    diff --git a/kernel/module.c b/kernel/module.c
    index 3965511..c33a113 100644
    --- a/kernel/module.c
    +++ b/kernel/module.c
    @@ -774,7 +774,12 @@ static int try_stop_module(struct module *mod, int flags, int *forced)

    unsigned long module_refcount(struct module *mod)
    {
    - return (unsigned long)atomic_read(&mod->refcnt) - MODULE_REF_BASE;
    + unsigned long ret = atomic_read(&mod->refcnt);
    +
    + if (ret == 0)
    + /* ref is already zero (probably in module exit) */
    + return 0;
    + return ret - MODULE_REF_BASE;
    }
    EXPORT_SYMBOL(module_refcount);




    \
     
     \ /
      Last update: 2015-01-18 18:21    [W:3.396 / U:0.052 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site