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    SubjectRe: device_remove_file and disconnect
    On Thu, Jun 30, 2005 at 10:31:44PM +0200, matthieu castet wrote:
    > >Then they should be fixed. Any specific examples?
    > >
    > >
    > I am a little lasy to list all, but some drivers in driver/usb should
    > have this problem : the first driver I look : ./misc/phidgetkit.c do
    > [1]. So sysfs read don't check if to_usb_interface or usb_get_intfdata
    > return NULL pointer...
    > And it is a bit your fault, as many developper should have read your
    > great tutorial [2] ;)

    You are correct, I'll go fix those drivers, thanks for pointing it out.
    Others pointed out the same thing this week at OLS :)

    > >>Also I always see driver free their privatre data in device disconnect,
    > >>so if read/write from sysfs aren't serialized with device disconnect
    > >>there are still a possible race like I show in my example.
    > >
    > >
    > >Yes, you are correct. Again, any specific drivers you see with this
    > >problem?
    > I believe near all drivers that use sysfs via device_create_file, as I
    > never see them use mutex in read/write in order to check there aren't in
    > the same time in their disconnect that could free there private data
    > when they do operation on it...
    > Couldn't be possible the make device_remove_file blocking until all the
    > open file are closed ?

    Hm, do we even know that those files are opened then? I'll poke around
    in sysfs and see if we could do that.


    greg k-h
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