[PATCH AUTOSEL 6.1 20/28] iommu/mediatek: Fix crash on isr after kexec()

From: Sasha Levin
Date: Tue Dec 27 2022 - 15:35:06 EST


From: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>

[ Upstream commit 00ef8885a945c37551547d8ac8361cacd20c4e42 ]

If the system is rebooted via isr(), the IRQ handler might
be triggered before the domain is initialized. Resulting on
an invalid memory access error.

Fix:
[ 0.500930] Unable to handle kernel read from unreadable memory at virtual address 0000000000000070
[ 0.501166] Call trace:
[ 0.501174] report_iommu_fault+0x28/0xfc
[ 0.501180] mtk_iommu_isr+0x10c/0x1c0

Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Link: https://lore.kernel.org/r/20221125-mtk-iommu-v2-0-e168dff7d43e@xxxxxxxxxxxx
[ joro: Fixed spelling in commit message ]
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/iommu/mtk_iommu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 2ab2ecfe01f8..3d913ab5029c 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -454,7 +454,7 @@ static irqreturn_t mtk_iommu_isr(int irq, void *dev_id)
fault_larb = data->plat_data->larbid_remap[fault_larb][sub_comm];
}

- if (report_iommu_fault(&dom->domain, bank->parent_dev, fault_iova,
+ if (!dom || report_iommu_fault(&dom->domain, bank->parent_dev, fault_iova,
write ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ)) {
dev_err_ratelimited(
bank->parent_dev,
--
2.35.1