From: Miles Chen miles.chen@mediatek.com
[ Upstream commit de78657e16f41417da9332f09c2d67d100096939 ]
When larbdev is NULL (in the case I hit, the node is incorrectly set iommus = <&iommu NUM>), it will cause device_link_add() fail and kernel crashes when we try to print dev_name(larbdev).
Let's fail the probe if a larbdev is NULL to avoid invalid inputs from dts.
It should work for normal correct setting and avoid the crash caused by my incorrect setting.
Error log: [ 18.189042][ T301] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 ... [ 18.344519][ T301] pstate: a0400005 (NzCv daif +PAN -UAO) [ 18.345213][ T301] pc : mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] [ 18.346050][ T301] lr : mtk_iommu_probe_device+0xd0/0x118 [mtk_iommu] [ 18.346884][ T301] sp : ffffffc00a5635e0 [ 18.347392][ T301] x29: ffffffc00a5635e0 x28: ffffffd44a46c1d8 [ 18.348156][ T301] x27: ffffff80c39a8000 x26: ffffffd44a80cc38 [ 18.348917][ T301] x25: 0000000000000000 x24: ffffffd44a80cc38 [ 18.349677][ T301] x23: ffffffd44e4da4c6 x22: ffffffd44a80cc38 [ 18.350438][ T301] x21: ffffff80cecd1880 x20: 0000000000000000 [ 18.351198][ T301] x19: ffffff80c439f010 x18: ffffffc00a50d0c0 [ 18.351959][ T301] x17: ffffffffffffffff x16: 0000000000000004 [ 18.352719][ T301] x15: 0000000000000004 x14: ffffffd44eb5d420 [ 18.353480][ T301] x13: 0000000000000ad2 x12: 0000000000000003 [ 18.354241][ T301] x11: 00000000fffffad2 x10: c0000000fffffad2 [ 18.355003][ T301] x9 : a0d288d8d7142d00 x8 : a0d288d8d7142d00 [ 18.355763][ T301] x7 : ffffffd44c2bc640 x6 : 0000000000000000 [ 18.356524][ T301] x5 : 0000000000000080 x4 : 0000000000000001 [ 18.357284][ T301] x3 : 0000000000000000 x2 : 0000000000000005 [ 18.358045][ T301] x1 : 0000000000000000 x0 : 0000000000000000 [ 18.360208][ T301] Hardware name: MT6873 (DT) [ 18.360771][ T301] Call trace: [ 18.361168][ T301] dump_backtrace+0xf8/0x1f0 [ 18.361737][ T301] dump_stack_lvl+0xa8/0x11c [ 18.362305][ T301] dump_stack+0x1c/0x2c [ 18.362816][ T301] mrdump_common_die+0x184/0x40c [mrdump] [ 18.363575][ T301] ipanic_die+0x24/0x38 [mrdump] [ 18.364230][ T301] atomic_notifier_call_chain+0x128/0x2b8 [ 18.364937][ T301] die+0x16c/0x568 [ 18.365394][ T301] __do_kernel_fault+0x1e8/0x214 [ 18.365402][ T301] do_page_fault+0xb8/0x678 [ 18.366934][ T301] do_translation_fault+0x48/0x64 [ 18.368645][ T301] do_mem_abort+0x68/0x148 [ 18.368652][ T301] el1_abort+0x40/0x64 [ 18.368660][ T301] el1h_64_sync_handler+0x54/0x88 [ 18.368668][ T301] el1h_64_sync+0x68/0x6c [ 18.368673][ T301] mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] ...
Cc: Robin Murphy robin.murphy@arm.com Cc: Yong Wu yong.wu@mediatek.com Reported-by: kernel test robot lkp@intel.com Fixes: 635319a4a744 ("media: iommu/mediatek: Add device_link between the consumer and the larb devices") Signed-off-by: Miles Chen miles.chen@mediatek.com Reviewed-by: Yong Wu yong.wu@mediatek.com Reviewed-by: AngeloGioacchino Del Regno angelogioacchino.delregno@collabora.com Link: https://lore.kernel.org/r/20220505132731.21628-1-miles.chen@mediatek.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/mtk_iommu.c | 6 ++++++ drivers/iommu/mtk_iommu_v1.c | 7 +++++++ 2 files changed, 13 insertions(+)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c index 3413cc98e57e..1a31f4707222 100644 --- a/drivers/iommu/mtk_iommu.c +++ b/drivers/iommu/mtk_iommu.c @@ -581,6 +581,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) * All the ports in each a device should be in the same larbs. */ larbid = MTK_M4U_TO_LARB(fwspec->ids[0]); + if (larbid >= MTK_LARB_NR_MAX) + return ERR_PTR(-EINVAL); + for (i = 1; i < fwspec->num_ids; i++) { larbidx = MTK_M4U_TO_LARB(fwspec->ids[i]); if (larbid != larbidx) { @@ -590,6 +593,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) } } larbdev = data->larb_imu[larbid].dev; + if (!larbdev) + return ERR_PTR(-EINVAL); + link = device_link_add(dev, larbdev, DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); if (!link) diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c index ecff800656e6..74563f689fbd 100644 --- a/drivers/iommu/mtk_iommu_v1.c +++ b/drivers/iommu/mtk_iommu_v1.c @@ -80,6 +80,7 @@ /* MTK generation one iommu HW only support 4K size mapping */ #define MT2701_IOMMU_PAGE_SHIFT 12 #define MT2701_IOMMU_PAGE_SIZE (1UL << MT2701_IOMMU_PAGE_SHIFT) +#define MT2701_LARB_NR_MAX 3
/* * MTK m4u support 4GB iova address space, and only support 4K page @@ -457,6 +458,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
/* Link the consumer device with the smi-larb device(supplier) */ larbid = mt2701_m4u_to_larb(fwspec->ids[0]); + if (larbid >= MT2701_LARB_NR_MAX) + return ERR_PTR(-EINVAL); + for (idx = 1; idx < fwspec->num_ids; idx++) { larbidx = mt2701_m4u_to_larb(fwspec->ids[idx]); if (larbid != larbidx) { @@ -467,6 +471,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev) }
larbdev = data->larb_imu[larbid].dev; + if (!larbdev) + return ERR_PTR(-EINVAL); + link = device_link_add(dev, larbdev, DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS); if (!link)