Author: kib
Date: Wed Mar  9 10:19:32 2016
New Revision: 296561
URL: https://svnweb.freebsd.org/changeset/base/296561

Log:
  MFC r296009:
  In bpf_getdltlist(), do not call copyout(9) while holding bpf lock.
  Copy the data into temprorary malloced buffer and drop the lock for
  copyout.

Modified:
  stable/10/sys/net/bpf.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/net/bpf.c
==============================================================================
--- stable/10/sys/net/bpf.c     Wed Mar  9 10:14:53 2016        (r296560)
+++ stable/10/sys/net/bpf.c     Wed Mar  9 10:19:32 2016        (r296561)
@@ -2616,26 +2616,44 @@ bpf_ifdetach(void *arg __unused, struct 
 static int
 bpf_getdltlist(struct bpf_d *d, struct bpf_dltlist *bfl)
 {
-       int n, error;
        struct ifnet *ifp;
        struct bpf_if *bp;
+       u_int *lst;
+       int error, n, n1;
 
        BPF_LOCK_ASSERT();
 
        ifp = d->bd_bif->bif_ifp;
+again:
+       n1 = 0;
+       LIST_FOREACH(bp, &bpf_iflist, bif_next) {
+               if (bp->bif_ifp == ifp)
+                       n1++;
+       }
+       if (bfl->bfl_list == NULL) {
+               bfl->bfl_len = n1;
+               return (0);
+       }
+       if (n1 > bfl->bfl_len)
+               return (ENOMEM);
+       BPF_UNLOCK();
+       lst = malloc(n1 * sizeof(u_int), M_TEMP, M_WAITOK);
        n = 0;
-       error = 0;
+       BPF_LOCK();
        LIST_FOREACH(bp, &bpf_iflist, bif_next) {
                if (bp->bif_ifp != ifp)
                        continue;
-               if (bfl->bfl_list != NULL) {
-                       if (n >= bfl->bfl_len)
-                               return (ENOMEM);
-                       error = copyout(&bp->bif_dlt,
-                           bfl->bfl_list + n, sizeof(u_int));
+               if (n > n1) {
+                       free(lst, M_TEMP);
+                       goto again;
                }
+               lst[n] = bp->bif_dlt;
                n++;
        }
+       BPF_UNLOCK();
+       error = copyout(lst, bfl->bfl_list, sizeof(u_int) * n);
+       free(lst, M_TEMP);
+       BPF_LOCK();
        bfl->bfl_len = n;
        return (error);
 }
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