tg3-fix-deadlock_in_tg3_change_mtu.patch

   1 From patchwork Wed Feb 26 12:23:50 2014
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   5 Subject: [3.11.y.z, extended,
   6  stable] Patch "tg3: Fix deadlock in tg3_change_mtu()" has been added
   7  to staging queue
   8 From: Luis Henriques <luis.henriques@canonical.com>
   9 Date: Wed, 26 Feb 2014 12:23:50 +0000
  10
  11 This is a note to let you know that I have just added a patch titled
  12
  13     tg3: Fix deadlock in tg3_change_mtu()
  14
  15 to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree
  16 which can be found at:
  17
  18  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue
  19
  20 If you, or anyone else, feels it should not be added to this tree, please
  21 reply to this email.
  22
  23 For more information about the 3.11.y.z tree, see
  24 https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
  25
  26 Thanks.
  27 -Luis
  28
  29 ------
  30
  31 >From e4075c63a28b56215afce0dee915a036a14baeab Mon Sep 17 00:00:00 2001
  32 From: Nithin Sujir <nsujir@broadcom.com>
  33 Date: Thu, 6 Feb 2014 14:13:05 -0800
  34 Subject: tg3: Fix deadlock in tg3_change_mtu()
  35
  36 commit c6993dfd7db9b0c6b7ca7503a56fda9236a4710f upstream.
  37
  38 Quoting David Vrabel -
  39 "5780 cards cannot have jumbo frames and TSO enabled together.  When
  40 jumbo frames are enabled by setting the MTU, the TSO feature must be
  41 cleared.  This is done indirectly by calling netdev_update_features()
  42 which will call tg3_fix_features() to actually clear the flags.
  43
  44 netdev_update_features() will also trigger a new netlink message for the
  45 feature change event which will result in a call to tg3_get_stats64()
  46 which deadlocks on the tg3 lock."
  47
  48 tg3_set_mtu() does not need to be under the tg3 lock since converting
  49 the flags to use set_bit(). Move it out to after tg3_netif_stop().
  50
  51 Reported-by: David Vrabel <david.vrabel@citrix.com>
  52 Tested-by: David Vrabel <david.vrabel@citrix.com>
  53 Signed-off-by: Michael Chan <mchan@broadcom.com>
  54 Signed-off-by: Nithin Nayak Sujir <nsujir@broadcom.com>
  55 Signed-off-by: David S. Miller <davem@davemloft.net>
  56 Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
  57 ---
  58  drivers/net/ethernet/broadcom/tg3.c | 4 ++--
  59  1 file changed, 2 insertions(+), 2 deletions(-)
  60
  61 --
  62 1.9.0
  63
  64 diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
  65 index f9aec90..849b141 100644
  66 --- a/drivers/net/ethernet/broadcom/tg3.c
  67 +++ b/drivers/net/ethernet/broadcom/tg3.c
  68 @@ -13907,12 +13907,12 @@ static int tg3_change_mtu(struct net_device *dev, int new_mtu)
  69
  70         tg3_netif_stop(tp);
  71
  72 +       tg3_set_mtu(dev, tp, new_mtu);
  73 +
  74         tg3_full_lock(tp, 1);
  75
  76         tg3_halt(tp, RESET_KIND_SHUTDOWN, 1);
  77
  78 -       tg3_set_mtu(dev, tp, new_mtu);
  79 -
  80         /* Reset PHY, otherwise the read DMA engine will be in a mode that
  81          * breaks all requests to 256 bytes.
  82          */