queue-4.19/virtio_pci-fix-a-null-pointer-reference-in-vp_del_vq.patch

   1 From 9c97b03462499e871671ac5b06cd96086928a0d3 Mon Sep 17 00:00:00 2001
   2 From: Longpeng <longpeng2@huawei.com>
   3 Date: Sat, 9 Mar 2019 15:17:40 +0800
   4 Subject: virtio_pci: fix a NULL pointer reference in vp_del_vqs
   5
   6 [ Upstream commit 6a8aae68c87349dbbcd46eac380bc43cdb98a13b ]
   7
   8 If the msix_affinity_masks is alloced failed, then we'll
   9 try to free some resources in vp_free_vectors() that may
  10 access it directly.
  11
  12 We met the following stack in our production:
  13 [   29.296767] BUG: unable to handle kernel NULL pointer dereference at  (null)
  14 [   29.311151] IP: [<ffffffffc04fe35a>] vp_free_vectors+0x6a/0x150 [virtio_pci]
  15 [   29.324787] PGD 0
  16 [   29.333224] Oops: 0000 [#1] SMP
  17 [...]
  18 [   29.425175] RIP: 0010:[<ffffffffc04fe35a>]  [<ffffffffc04fe35a>] vp_free_vectors+0x6a/0x150 [virtio_pci]
  19 [   29.441405] RSP: 0018:ffff9a55c2dcfa10  EFLAGS: 00010206
  20 [   29.453491] RAX: 0000000000000000 RBX: ffff9a55c322c400 RCX: 0000000000000000
  21 [   29.467488] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9a55c322c400
  22 [   29.481461] RBP: ffff9a55c2dcfa20 R08: 0000000000000000 R09: ffffc1b6806ff020
  23 [   29.495427] R10: 0000000000000e95 R11: 0000000000aaaaaa R12: 0000000000000000
  24 [   29.509414] R13: 0000000000010000 R14: ffff9a55bd2d9e98 R15: ffff9a55c322c400
  25 [   29.523407] FS:  00007fdcba69f8c0(0000) GS:ffff9a55c2840000(0000) knlGS:0000000000000000
  26 [   29.538472] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  27 [   29.551621] CR2: 0000000000000000 CR3: 000000003ce52000 CR4: 00000000003607a0
  28 [   29.565886] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  29 [   29.580055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  30 [   29.594122] Call Trace:
  31 [   29.603446]  [<ffffffffc04fe8a2>] vp_request_msix_vectors+0xe2/0x260 [virtio_pci]
  32 [   29.618017]  [<ffffffffc04fedc5>] vp_try_to_find_vqs+0x95/0x3b0 [virtio_pci]
  33 [   29.632152]  [<ffffffffc04ff117>] vp_find_vqs+0x37/0xb0 [virtio_pci]
  34 [   29.645582]  [<ffffffffc057bf63>] init_vq+0x153/0x260 [virtio_blk]
  35 [   29.658831]  [<ffffffffc057c1e8>] virtblk_probe+0xe8/0x87f [virtio_blk]
  36 [...]
  37
  38 Cc: Gonglei <arei.gonglei@huawei.com>
  39 Signed-off-by: Longpeng <longpeng2@huawei.com>
  40 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
  41 Reviewed-by: Gonglei <arei.gonglei@huawei.com>
  42 Signed-off-by: Sasha Levin <sashal@kernel.org>
  43 ---
  44  drivers/virtio/virtio_pci_common.c | 8 +++++---
  45  1 file changed, 5 insertions(+), 3 deletions(-)
  46
  47 diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
  48 index 465a6f5142cc5..45b04bc91f248 100644
  49 --- a/drivers/virtio/virtio_pci_common.c
  50 +++ b/drivers/virtio/virtio_pci_common.c
  51 @@ -255,9 +255,11 @@ void vp_del_vqs(struct virtio_device *vdev)
  52         for (i = 0; i < vp_dev->msix_used_vectors; ++i)
  53                 free_irq(pci_irq_vector(vp_dev->pci_dev, i), vp_dev);
  54
  55 -       for (i = 0; i < vp_dev->msix_vectors; i++)
  56 -               if (vp_dev->msix_affinity_masks[i])
  57 -                       free_cpumask_var(vp_dev->msix_affinity_masks[i]);
  58 +       if (vp_dev->msix_affinity_masks) {
  59 +               for (i = 0; i < vp_dev->msix_vectors; i++)
  60 +                       if (vp_dev->msix_affinity_masks[i])
  61 +                               free_cpumask_var(vp_dev->msix_affinity_masks[i]);
  62 +       }
  63
  64         if (vp_dev->msix_enabled) {
  65                 /* Disable the vector used for configuration */
  66 --
  67 2.20.1
  68