From fe532395c4a0ee21d3487f23f48446ee16df1a44 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 28 Oct 2021 10:37:16 +0800 Subject: [PATCH] iommu/arm-smmu: Prevent forced unbinding of Arm SMMU drivers mainline inclusion from mainline-v5.5-rc1 commit 34debdca68efd5625a2fcea7df1a215591a01f80 category: bugfix bugzilla: 95382 CVE: NA ------------------------------------------------- Forcefully unbinding the Arm SMMU drivers is a pretty dangerous operation, since it will likely lead to catastrophic failure for any DMA devices mastering through the SMMU being unbound. When the driver then attempts to "handle" the fatal faults, it's very easy to trip over dead data structures, leading to use-after-free. On John's machine, he reports that the machine was "unusable" due to loss of the storage controller following a forced unbind of the SMMUv3 driver: | # cd ./bus/platform/drivers/arm-smmu-v3 | # echo arm-smmu-v3.0.auto > unbind | hisi_sas_v2_hw HISI0162:01: CQE_AXI_W_ERR (0x800) found! | platform arm-smmu-v3.0.auto: CMD_SYNC timeout at 0x00000146 | [hwprod 0x00000146, hwcons 0x00000000] Prevent this forced unbinding of the drivers by setting "suppress_bind_attrs" to true. Link: https://lore.kernel.org/lkml/06dfd385-1af0-3106-4cc5-6a5b8e864759@huawei.com Reported-by: John Garry Signed-off-by: Will Deacon Tested-by: John Garry # smmu v3 Reviewed-by: Greg Kroah-Hartman Signed-off-by: Joerg Roedel Signed-off-by: Nanyong Sun Reviewed-by: Kefeng Wang Signed-off-by: Yang Yingliang --- drivers/iommu/arm-smmu-v3.c | 5 +++-- drivers/iommu/arm-smmu.c | 7 ++++--- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index f3d26e4d8d2c..560980c54014 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -4529,8 +4529,9 @@ MODULE_DEVICE_TABLE(of, arm_smmu_of_match); static struct platform_driver arm_smmu_driver = { .driver = { - .name = "arm-smmu-v3", - .of_match_table = of_match_ptr(arm_smmu_of_match), + .name = "arm-smmu-v3", + .of_match_table = of_match_ptr(arm_smmu_of_match), + .suppress_bind_attrs = true, }, .probe = arm_smmu_device_probe, .remove = arm_smmu_device_remove, diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 451075bb1b3c..8a268ab82ef0 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -2287,9 +2287,10 @@ static SIMPLE_DEV_PM_OPS(arm_smmu_pm_ops, NULL, arm_smmu_pm_resume); static struct platform_driver arm_smmu_driver = { .driver = { - .name = "arm-smmu", - .of_match_table = of_match_ptr(arm_smmu_of_match), - .pm = &arm_smmu_pm_ops, + .name = "arm-smmu", + .of_match_table = of_match_ptr(arm_smmu_of_match), + .pm = &arm_smmu_pm_ops, + .suppress_bind_attrs = true, }, .probe = arm_smmu_device_probe, .remove = arm_smmu_device_remove, -- GitLab