Koos Vriezen 5003ae1e73 iommu/vt-d: Fix NULL pointer dereference in device_to_iommu
The function device_to_iommu() in the Intel VT-d driver
lacks a NULL-ptr check, resulting in this oops at boot on
some platforms:

 BUG: unable to handle kernel NULL pointer dereference at 00000000000007ab
 IP: [<ffffffff8132234a>] device_to_iommu+0x11a/0x1a0
 PGD 0

 [...]

 Call Trace:
   ? find_or_alloc_domain.constprop.29+0x1a/0x300
   ? dw_dma_probe+0x561/0x580 [dw_dmac_core]
   ? __get_valid_domain_for_dev+0x39/0x120
   ? __intel_map_single+0x138/0x180
   ? intel_alloc_coherent+0xb6/0x120
   ? sst_hsw_dsp_init+0x173/0x420 [snd_soc_sst_haswell_pcm]
   ? mutex_lock+0x9/0x30
   ? kernfs_add_one+0xdb/0x130
   ? devres_add+0x19/0x60
   ? hsw_pcm_dev_probe+0x46/0xd0 [snd_soc_sst_haswell_pcm]
   ? platform_drv_probe+0x30/0x90
   ? driver_probe_device+0x1ed/0x2b0
   ? __driver_attach+0x8f/0xa0
   ? driver_probe_device+0x2b0/0x2b0
   ? bus_for_each_dev+0x55/0x90
   ? bus_add_driver+0x110/0x210
   ? 0xffffffffa11ea000
   ? driver_register+0x52/0xc0
   ? 0xffffffffa11ea000
   ? do_one_initcall+0x32/0x130
   ? free_vmap_area_noflush+0x37/0x70
   ? kmem_cache_alloc+0x88/0xd0
   ? do_init_module+0x51/0x1c4
   ? load_module+0x1ee9/0x2430
   ? show_taint+0x20/0x20
   ? kernel_read_file+0xfd/0x190
   ? SyS_finit_module+0xa3/0xb0
   ? do_syscall_64+0x4a/0xb0
   ? entry_SYSCALL64_slow_path+0x25/0x25
 Code: 78 ff ff ff 4d 85 c0 74 ee 49 8b 5a 10 0f b6 9b e0 00 00 00 41 38 98 e0 00 00 00 77 da 0f b6 eb 49 39 a8 88 00 00 00 72 ce eb 8f <41> f6 82 ab 07 00 00 04 0f 85 76 ff ff ff 0f b6 4d 08 88 0e 49
 RIP  [<ffffffff8132234a>] device_to_iommu+0x11a/0x1a0
  RSP <ffffc90001457a78>
 CR2: 00000000000007ab
 ---[ end trace 16f974b6d58d0aad ]---

Add the missing pointer check.

Fixes: 1c387188c6 ("iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions")
Signed-off-by: Koos Vriezen <koos.vriezen@gmail.com>
Cc: stable@vger.kernel.org # 4.8.15+
Signed-off-by: Joerg Roedel <jroedel@suse.de>
2017-03-22 12:01:42 +01:00
2017-02-13 12:24:56 -05:00
2016-05-23 17:04:14 -07:00
2017-03-19 19:09:39 -07:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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