This is a note to let you know that I've just added the patch titled iommu/vt-d: Fix NULL pointer dereference in device_to_iommu to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iommu-vt-d-fix-null-pointer-dereference-in-device_to_iommu.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 5003ae1e735e6bfe4679d9bed6846274f322e77e Mon Sep 17 00:00:00 2001 From: Koos Vriezen <koos.vriezen@xxxxxxxxx> Date: Wed, 1 Mar 2017 21:02:50 +0100 Subject: iommu/vt-d: Fix NULL pointer dereference in device_to_iommu From: Koos Vriezen <koos.vriezen@xxxxxxxxx> commit 5003ae1e735e6bfe4679d9bed6846274f322e77e upstream. 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: 1c387188c60f53b338c20eee32db055dfe022a9b ("iommu/vt-d: Fix IOMMU lookup for SR-IOV Virtual Functions") Signed-off-by: Koos Vriezen <koos.vriezen@xxxxxxxxx> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iommu/intel-iommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -908,7 +908,7 @@ static struct intel_iommu *device_to_iom * 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; Patches currently in stable-queue which might be from koos.vriezen@xxxxxxxxx are queue-4.4/iommu-vt-d-fix-null-pointer-dereference-in-device_to_iommu.patch