In addition to checking for a null pointer, verify that info does not have the value DEFER_DEVICE_DOMAIN_INFO or DUMMY_DEVICE_DOMAIN_INFO. If info has one of those values __dmar_remove_one_dev_info will panic when trying to access a member of the device_domain_info struct.
[ 1.464241] BUG: unable to handle kernel NULL pointer dereference at 000000000000004e [ 1.464241] PGD 0 P4D 0 [ 1.464241] Oops: 0000 [#1] SMP PTI [ 1.464241] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W --------- - - 4.18.0-160.el8.x86_64 #1 [ 1.464241] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 07/21/2019 [ 1.464241] RIP: 0010:__dmar_remove_one_dev_info+0x27/0x250 [ 1.464241] Code: 00 00 00 0f 1f 44 00 00 8b 05 35 ec 75 01 41 56 41 55 41 54 55 53 85 c0 0f 84 99 01 00 00 48 85 ff 0f 84 92 01 00 00 48 89 fb <4c> 8b 67 50 48 8b 6f 58 $ [ 1.464241] RSP: 0000:ffffc900000dfd10 EFLAGS: 00010082 [ 1.464241] RAX: 0000000000000001 RBX: fffffffffffffffe RCX: 0000000000000000 [ 1.464241] RDX: 0000000000000001 RSI: 0000000000000004 RDI: fffffffffffffffe [ 1.464241] RBP: ffff88ec7a72f368 R08: 0000000000000457 R09: 0000000000000039 [ 1.464241] R10: 0000000000000000 R11: ffffc900000dfa58 R12: ffff88ec7a0eec20 [ 1.464241] R13: ffff88ec6fd0eab0 R14: ffffffff81eae980 R15: 0000000000000000 [ 1.464241] FS: 0000000000000000(0000) GS:ffff88ec7a600000(0000) knlGS:0000000000000000 [ 1.464241] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1.464241] CR2: 000000000000004e CR3: 0000006c7900a001 C 00000000001606b0 [ 1.464241] Call Trace: [ 1.464241] dmar_remove_one_dev_info.isra.68+0x27/0x40 [ 1.464241] intel_iommu_add_device+0x124/0x180 [ 1.464241] ? iommu_probe_device+0x40/0x40 [ 1.464241] add_iommu_group+0xa/0x20 [ 1.464241] bus_for_each_dev+0x77/0xc0 [ 1.464241] ? down_write+0xe/0x40 [ 1.464241] bus_set_iommu+0x85/0xc0 [ 1.464241] intel_iommu_init+0x4b4/0x777 [ 1.464241] ? e820__memblock_setup+0x63/0x63 [ 1.464241] ? do_early_param+0x91/0x91 [ 1.464241] pci_iommu_init+0x19/0x45 [ 1.464241] do_one_initcall+0x46/0x1c3 [ 1.464241] ? do_early_param+0x91/0x91 [ 1.464241] kernel_init_freeable+0x1af/0x258 [ 1.464241] ? rest_init+0xaa/0xaa [ 1.464241] kernel_init+0xa/0x107 [ 1.464241] ret_from_fork+0x35/0x40 [ 1.464241] Modules linked in: [ 1.464241] CR2: 000000000000004e [ 1.464241] ---[ end trace 0927d2ba8b8032b5 ]---
Cc: Joerg Roedel jroedel@suse.de Cc: Lu Baolu baolu.lu@linux.intel.com Cc: David Woodhouse dwmw2@infradead.org Cc: stable@vger.kernel.org # v5.3+ Cc: iommu@lists.linux-foundation.org Fixes: ae23bfb68f28 ("iommu/vt-d: Detach domain before using a private one") Signed-off-by: Jerry Snitselaar jsnitsel@redhat.com --- drivers/iommu/intel-iommu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 0c8d81f56a30..e42a09794fa2 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -5163,7 +5163,8 @@ static void dmar_remove_one_dev_info(struct device *dev)
spin_lock_irqsave(&device_domain_lock, flags); info = dev->archdata.iommu; - if (info) + if (info && info != DEFER_DEVICE_DOMAIN_INFO + && info != DUMMY_DEVICE_DOMAIN_INFO) __dmar_remove_one_dev_info(info); spin_unlock_irqrestore(&device_domain_lock, flags); }