lkml.org 
[lkml]   [2007]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: Possible "struct pid" leak from tty_io.c
    On 13/03/07, Eric W. Biederman <ebiederm@xmission.com> wrote:
    > "Catalin Marinas" <catalin.marinas@gmail.com> writes:
    > > void proc_clear_tty(struct task_struct *p)
    > > {
    > > + struct tty_struct *tty;
    > > +
    > > spin_lock_irq(&p->sighand->siglock);
    > > + tty = p->signal->tty;
    > > + if (tty) {
    > > + put_pid(tty->session);
    > > + put_pid(tty->pgrp);
    > > + }
    > > p->signal->tty = NULL;
    > > spin_unlock_irq(&p->sighand->siglock);
    > > }
    >
    > This patch can't be right. Not the way proc_clear_tty is called
    > once for each process in the session, plus we aren't clearing
    > tty->session and tty->pgrp here.
    >
    > If the above patch works it's a fluke.

    I looked at the logs and the pointer isn't freed indeed. It is just a
    false negative in kmemleak and it would appear as a leak at some
    point. But the previous patch (do_tty_hangup) seems to fix one of the
    leaks.

    For the 2nd leak, proc_set_tty is called and, for symmetry, I added
    put_pid in proc_clear_tty (but without any deep thought). I also
    haven't checked any lockdep issues with adding put_pid when
    p->sighand->siglock is held.

    --
    Catalin
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2007-03-14 11:03    [W:0.026 / U:90.364 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site