On Jan 24, 2018 6:08 PM, "Kristof Provost" <k...@freebsd.org> wrote:
On 25 Jan 2018, at 11:34, Ian Lepore wrote: > On Wed, 2018-01-24 at 16:13 -0800, Gleb Smirnoff wrote: > >> (r328313) >> K> @@ -1613,6 +1613,7 @@ int >> K> pf_unlink_state(struct pf_state *s, u_int flags) >> K> { >> K> struct pf_idhash *ih = &V_pf_idhash[PF_IDHASH(s)]; >> K> + int last; >> K> >> K> if ((flags & PF_ENTER_LOCKED) == 0) >> K> PF_HASHROW_LOCK(ih); >> K> @@ -1653,7 +1654,8 @@ pf_unlink_state(struct pf_state *s, u_int >> flags) >> K> PF_HASHROW_UNLOCK(ih); >> K> >> K> pf_detach_state(s); >> K> - refcount_release(&s->refs); >> K> + last = refcount_release(&s->refs); >> K> + KASSERT(last == 0, ("Incorrect state reference count")); >> K> >> K> return (pf_release_state(s)); >> K> } >> >> IMHO, we shouldn't emit extra code to please Coverity. We can mark it >> as a false positive in the interface. It may make sense to add a >> comment >> for a human to explain why return isn't checked here. >> >> > Not to mention that when KASSERT compiles to nothing, what you're left > with is a "defined but not used" warning for 'last'. > > I’d really like to keep the KASSERT(), because this is the sort of thing that could go wrong, and the assertion would be helpful. I suppose I could wrap last in #ifdef INVARIANTS, but that’s rather ugly too. Asserting that the refcount is at least 1 when entering pf_release_state() would express the same, but that’s also problematic. Of course, errors should trigger the KASSERT() in refcount_release(), so I think I may have convinced myself that the KASSERT() can in fact be removed and replaced with (void)refcount_release() and a comment explaining why this refcount_release() can never return 1. It would be good to have a Coverty cheer sheet so we know how to annotate this stuff correctly in the source. I've started fumbling my way through for the boot loader and devmatch changes... Warner _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"