From fcb8a3a2e689c0a1aa317b24fc10b7e3b42fa1d4 Mon Sep 17 00:00:00 2001 From: brian Date: Wed, 20 Jun 2001 10:06:28 +0000 Subject: Close a race where we were releasing the unit resource at the start of tunclose() rather than the end, and tunopen() grabbed that unit before tunclose() finished (one process is allocating it while another is freeing it!). It may be worth hanging some sort of rw mutex around all specinfo calls where d_close and the detach handler get a write lock and all other functions get a read lock. This would guarantee certain levels of ``atomicity'' (is that a word?) that people may expect (I believe Solaris does something like this). --- sys/net/if_tun.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'sys/net') diff --git a/sys/net/if_tun.c b/sys/net/if_tun.c index 0194995..68cef88 100644 --- a/sys/net/if_tun.c +++ b/sys/net/if_tun.c @@ -307,8 +307,7 @@ tunclose(dev_t dev, int foo, int bar, struct proc *p) tp = dev->si_drv1; ifp = &tp->tun_if; - err = rman_release_resource(tp->r_unit); - KASSERT(err == 0, ("Unit %d not marked open", ifp->if_unit)); + KASSERT(tp->r_unit, ("Unit %d not marked open", ifp->if_unit)); tp->tun_flags &= ~TUN_OPEN; tp->tun_pid = 0; @@ -340,6 +339,9 @@ tunclose(dev_t dev, int foo, int bar, struct proc *p) selwakeup(&tp->tun_rsel); TUNDEBUG ("%s%d: closed\n", ifp->if_name, ifp->if_unit); + err = rman_release_resource(tp->r_unit); + KASSERT(err == 0, ("Unit %d failed to release", ifp->if_unit)); + return (0); } -- cgit v1.1