releases/3.3.4/net_sched-gred-fix-oops-in-gred_dump-in-wred-mode.patch

   1 From d65ba13406233f881bc212640b54bbb87c52141b Mon Sep 17 00:00:00 2001
   2 From: David Ward <david.ward@ll.mit.edu>
   3 Date: Sun, 15 Apr 2012 12:31:45 +0000
   4 Subject: [PATCH 19/28] net_sched: gred: Fix oops in gred_dump() in WRED mode
   5
   6
   7 From: David Ward <david.ward@ll.mit.edu>
   8
   9 [ Upstream commit 244b65dbfede788f2fa3fe2463c44d0809e97c6b ]
  10
  11 A parameter set exists for WRED mode, called wred_set, to hold the same
  12 values for qavg and qidlestart across all VQs. The WRED mode values had
  13 been previously held in the VQ for the default DP. After these values
  14 were moved to wred_set, the VQ for the default DP was no longer created
  15 automatically (so that it could be omitted on purpose, to have packets
  16 in the default DP enqueued directly to the device without using RED).
  17
  18 However, gred_dump() was overlooked during that change; in WRED mode it
  19 still reads qavg/qidlestart from the VQ for the default DP, which might
  20 not even exist. As a result, this command sequence will cause an oops:
  21
  22 tc qdisc add dev $DEV handle $HANDLE parent $PARENT gred setup \
  23     DPs 3 default 2 grio
  24 tc qdisc change dev $DEV handle $HANDLE gred DP 0 prio 8 $RED_OPTIONS
  25 tc qdisc change dev $DEV handle $HANDLE gred DP 1 prio 8 $RED_OPTIONS
  26
  27 This fixes gred_dump() in WRED mode to use the values held in wred_set.
  28
  29 Signed-off-by: David Ward <david.ward@ll.mit.edu>
  30 Signed-off-by: David S. Miller <davem@davemloft.net>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  32 ---
  33  net/sched/sch_gred.c |    7 ++-----
  34  1 file changed, 2 insertions(+), 5 deletions(-)
  35
  36 --- a/net/sched/sch_gred.c
  37 +++ b/net/sched/sch_gred.c
  38 @@ -565,11 +565,8 @@ static int gred_dump(struct Qdisc *sch,
  39                 opt.packets     = q->packetsin;
  40                 opt.bytesin     = q->bytesin;
  41
  42 -               if (gred_wred_mode(table)) {
  43 -                       q->vars.qidlestart =
  44 -                               table->tab[table->def]->vars.qidlestart;
  45 -                       q->vars.qavg = table->tab[table->def]->vars.qavg;
  46 -               }
  47 +               if (gred_wred_mode(table))
  48 +                       gred_load_wred_set(table, q);
  49
  50                 opt.qave = red_calc_qavg(&q->parms, &q->vars, q->vars.qavg);
  51