Messages in this thread | | | Date | Mon, 10 Jul 2017 17:22:01 +0100 | From | Okash Khawaja <> | Subject | Re: [patch 0/3] Re: tty contention resulting from tty_open_by_device export |
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On Mon, Jul 10, 2017 at 01:33:07PM +0100, Okash Khawaja wrote: > > If the tty counts are being misreported then it would be better to fix > > the code to actually manage the counts properly. The core tty code is > > telling you that the tty is not in a valid state. While this is of > > itself a good API to have, the underlying reference miscounting ought > > IMHO to be fixed as well. > When opening from kernel, we don't use file pointer. The count mismatch > is between tty->count and #fd's. So opening from kernel leads to #fd's > being less than tty->count. I thought this difference is relevant to > user-space opening of tty, and not to kernel opening of tty. Can you > suggest how to address this mismatch? Idea is tty_kopen only ever returns a newly initialised tty - returned by tty_init_dev. Since the access is exclusive, tty->count shouldn't matter. When the caller is done with it, it calls tty_release_struct which frees up the tty itself.
But yes, all the while a tty is kopened, its tty->count and #fds will be unequal.
Thanks, Okash
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