From 5003ae1e735e6bfe4679d9bed6846274f322e77e Mon Sep 17 00:00:00 2001 From: Koos Vriezen Date: Wed, 1 Mar 2017 21:02:50 +0100 Subject: [PATCH] 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: [] 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 [] device_to_iommu+0x11a/0x1a0 RSP CR2: 00000000000007ab ---[ end trace 16f974b6d58d0aad ]--- Add the missing pointer check. Fixes: 1c387188c60f53b338c20eee32db055dfe022a9b ("iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions") Signed-off-by: Koos Vriezen Cc: stable@vger.kernel.org # 4.8.15+ Signed-off-by: Joerg Roedel --- drivers/iommu/intel-iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 238ad3447712..91d60493b57c 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -916,7 +916,7 @@ static struct intel_iommu *device_to_iommu(struct device *dev, u8 *bus, u8 *devf * which we used for the IOMMU lookup. Strictly speaking * we could do this for all PCI devices; we only need to * get the BDF# from the scope table for ACPI matches. */ - if (pdev->is_virtfn) + if (pdev && pdev->is_virtfn) goto got_pdev; *bus = drhd->devices[i].bus; -- 2.20.1