svn commit: r328313 - head/sys/netpfil/pf

[Gleb Smirnoff]

  Hi Kristof,

On Wed, Jan 24, 2018 at 04:29:17AM +0000, Kristof Provost wrote:
K> Author: kp
K> Date: Wed Jan 24 04:29:16 2018
K> New Revision: 328313
K> URL: https://svnweb.freebsd.org/changeset/base/328313
K> 
K> Log:
K>   pf: States have at least two references
K>   
K>   pf_unlink_state() releases a reference to the state without checking if
K>   this is the last reference. It can't be, because pf_state_insert()
K>   initialises it to two. KASSERT() that this is always the case.
K>   
K>   CID:	1347140
K> 
K> Modified:
K>   head/sys/netpfil/pf/pf.c
K> 
K> Modified: head/sys/netpfil/pf/pf.c
K> ==============================================================================
K> --- head/sys/netpfil/pf/pf.c	Wed Jan 24 03:09:56 2018	(r328312)
K> +++ head/sys/netpfil/pf/pf.c	Wed Jan 24 04:29:16 2018	(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.

-- 
Gleb Smirnoff