Author: lstewart
Date: Tue Jan 10 00:48:29 2012
New Revision: 229898
URL: http://svn.freebsd.org/changeset/base/229898
Log:
Consumers of bpfdetach() expect it to remove all bpf_if structs from the
bpf_iflist list which reference the specified ifnet. The existing
implementation
only removes the first matching bpf_if found in the list, effectively leaking
list entries if an ifnet has been bpfattach()ed multiple times with different
DLTs.
Fix the leak by performing the detach logic in a loop, stopping when all
bpf_if
structs referencing the specified ifnet have been detached and removed from
the
bpf_iflist list.
Whilst here, also:
- Remove the unnecessary "bp->bif_ifp == NULL" check, as a bpf_if should never
exist in the list with a NULL ifnet pointer.
- Except when INVARIANTS is in the kernel config, silently ignore the case
where
no bpf_if referencing the specified ifnet is found, as it is harmless and
does
not require user attention.
Reviewed by: csjp
MFC after: 1 week
Modified:
head/sys/net/bpf.c
Modified: head/sys/net/bpf.c
==============================================================================
--- head/sys/net/bpf.c Tue Jan 10 00:35:25 2012 (r229897)
+++ head/sys/net/bpf.c Tue Jan 10 00:48:29 2012 (r229898)
@@ -2253,33 +2253,42 @@ bpfdetach(struct ifnet *ifp)
{
struct bpf_if *bp;
struct bpf_d *d;
+#ifdef INVARIANTS
+ int ndetached;
- /* Locate BPF interface information */
- mtx_lock(&bpf_mtx);
- LIST_FOREACH(bp, &bpf_iflist, bif_next) {
- if (ifp == bp->bif_ifp)
- break;
- }
+ ndetached = 0;
+#endif
- /* Interface wasn't attached */
- if ((bp == NULL) || (bp->bif_ifp == NULL)) {
+ /* Find all bpf_if struct's which reference ifp and detach them. */
+ do {
+ mtx_lock(&bpf_mtx);
+ LIST_FOREACH(bp, &bpf_iflist, bif_next) {
+ if (ifp == bp->bif_ifp)
+ break;
+ }
+ if (bp != NULL)
+ LIST_REMOVE(bp, bif_next);
mtx_unlock(&bpf_mtx);
- printf("bpfdetach: %s was not attached\n", ifp->if_xname);
- return;
- }
-
- LIST_REMOVE(bp, bif_next);
- mtx_unlock(&bpf_mtx);
- while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
- bpf_detachd(d);
- BPFD_LOCK(d);
- bpf_wakeup(d);
- BPFD_UNLOCK(d);
- }
+ if (bp != NULL) {
+#ifdef INVARIANTS
+ ndetached++;
+#endif
+ while ((d = LIST_FIRST(&bp->bif_dlist)) != NULL) {
+ bpf_detachd(d);
+ BPFD_LOCK(d);
+ bpf_wakeup(d);
+ BPFD_UNLOCK(d);
+ }
+ mtx_destroy(&bp->bif_mtx);
+ free(bp, M_BPF);
+ }
+ } while (bp != NULL);
- mtx_destroy(&bp->bif_mtx);
- free(bp, M_BPF);
+#ifdef INVARIANTS
+ if (ndetached == 0)
+ printf("bpfdetach: %s was not attached\n", ifp->if_xname);
+#endif
}
/*
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