6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicolin Chen [ Upstream commit d4d05f55e9da646ec03adfa77260eb46f4163749 ] __tegra241_cmdqv_probe() uses devm_krealloc() to grow @smmu into the larger tegra241_cmdqv, which frees the original @smmu once it relocates. A failure after that returned NULL, and the caller then dereferenced the freed @smmu on its fallback path. Return an int and take @smmu by reference instead, then update *smmu to the reallocated pointer after devm_krealloc() succeeds, so the caller and its fallback path both use the live @smmu rather than the freed original. Fixes: 918eb5c856f6 ("iommu/arm-smmu-v3: Add in-kernel support for NVIDIA Tegra241 (Grace) CMDQV") Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Nicolin Chen Signed-off-by: Will Deacon Signed-off-by: Sasha Levin --- .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c | 54 +++++++++++-------- 1 file changed, 32 insertions(+), 22 deletions(-) diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c index 2b55a221c35a6..fdbd487848e64 100644 --- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c +++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c @@ -1015,16 +1015,22 @@ static int tegra241_cmdqv_init_structures(struct arm_smmu_device *smmu) static struct dentry *cmdqv_debugfs_dir; #endif -static struct arm_smmu_device * -__tegra241_cmdqv_probe(struct arm_smmu_device *smmu, struct resource *res, - int irq) +/* + * Probe the CMDQV and reallocate @smmu into the larger cmdqv->smmu. + * + * devm_krealloc() may relocate and free the original @smmu, so update *smmu to + * the new pointer once it succeeds. The error paths after it do the same, so a + * caller falling back keeps a live @smmu instead of the freed original. + */ +static int __tegra241_cmdqv_probe(struct arm_smmu_device **smmu, + struct resource *res, int irq) { static const struct arm_smmu_impl_ops init_ops = { .init_structures = tegra241_cmdqv_init_structures, .device_remove = tegra241_cmdqv_remove, }; - struct tegra241_cmdqv *cmdqv = NULL; - struct arm_smmu_device *new_smmu; + struct device *dev = (*smmu)->dev; + struct tegra241_cmdqv *cmdqv; void __iomem *base; u32 regval; int ret; @@ -1033,25 +1039,28 @@ __tegra241_cmdqv_probe(struct arm_smmu_device *smmu, struct resource *res, base = ioremap(res->start, resource_size(res)); if (!base) { - dev_err(smmu->dev, "failed to ioremap\n"); - return NULL; + dev_err(dev, "failed to ioremap\n"); + return -ENOMEM; } regval = readl(base + TEGRA241_CMDQV_CONFIG); if (disable_cmdqv) { - dev_info(smmu->dev, "Detected disable_cmdqv=true\n"); + dev_info(dev, "Detected disable_cmdqv=true\n"); writel(regval & ~CMDQV_EN, base + TEGRA241_CMDQV_CONFIG); + ret = -ENODEV; goto iounmap; } - cmdqv = devm_krealloc(smmu->dev, smmu, sizeof(*cmdqv), GFP_KERNEL); - if (!cmdqv) + cmdqv = devm_krealloc(dev, *smmu, sizeof(*cmdqv), GFP_KERNEL); + if (!cmdqv) { + ret = -ENOMEM; goto iounmap; - new_smmu = &cmdqv->smmu; + } + *smmu = &cmdqv->smmu; cmdqv->irq = irq; cmdqv->base = base; - cmdqv->dev = smmu->impl_dev; + cmdqv->dev = (*smmu)->impl_dev; cmdqv->base_phys = res->start; regval = readl_relaxed(REG_CMDQV(cmdqv, PARAM)); @@ -1063,8 +1072,10 @@ __tegra241_cmdqv_probe(struct arm_smmu_device *smmu, struct resource *res, cmdqv->vintfs = kcalloc(cmdqv->num_vintfs, sizeof(*cmdqv->vintfs), GFP_KERNEL); - if (!cmdqv->vintfs) + if (!cmdqv->vintfs) { + ret = -ENOMEM; goto iounmap; + } ida_init(&cmdqv->vintf_ids); @@ -1093,40 +1104,39 @@ __tegra241_cmdqv_probe(struct arm_smmu_device *smmu, struct resource *res, #endif /* Provide init-level ops only, until tegra241_cmdqv_init_structures */ - new_smmu->impl_ops = &init_ops; + cmdqv->smmu.impl_ops = &init_ops; - return new_smmu; + return 0; free_vintfs: ida_destroy(&cmdqv->vintf_ids); kfree(cmdqv->vintfs); iounmap: iounmap(base); - return NULL; + return ret; } struct arm_smmu_device *tegra241_cmdqv_probe(struct arm_smmu_device *smmu) { - struct arm_smmu_device *new_smmu; struct resource *res = NULL; - int irq; + int irq, ret; if (!smmu->dev->of_node) res = tegra241_cmdqv_find_acpi_resource(smmu->impl_dev, &irq); if (!res) goto out_fallback; - new_smmu = __tegra241_cmdqv_probe(smmu, res, irq); + ret = __tegra241_cmdqv_probe(&smmu, res, irq); kfree(res); - if (new_smmu) - return new_smmu; + if (!ret) + return smmu; out_fallback: dev_info(smmu->impl_dev, "Falling back to standard SMMU CMDQ\n"); smmu->options &= ~ARM_SMMU_OPT_TEGRA241_CMDQV; put_device(smmu->impl_dev); - return ERR_PTR(-ENODEV); + return smmu; } /* User space VINTF and VCMDQ Functions */ -- 2.53.0