From ac9a5d522bb80be50ea84965699e1c8257d745ce Mon Sep 17 00:00:00 2001 From: Yunfei Wang Date: Mon, 30 May 2022 20:07:45 +0800 Subject: iommu/dma: Fix race condition during iova_domain initialization When many devices share the same iova domain, iommu_dma_init_domain() may be called at the same time. The checking of iovad->start_pfn will all get false in iommu_dma_init_domain() and both enter init_iova_domain() to do iovad initialization. Fix this by protecting init_iova_domain() with iommu_dma_cookie->mutex. Exception backtrace: rb_insert_color(param1=0xFFFFFF80CD2BDB40, param3=1) + 64 init_iova_domain() + 180 iommu_setup_dma_ops() + 260 arch_setup_dma_ops() + 132 of_dma_configure_id() + 468 platform_dma_configure() + 32 really_probe() + 1168 driver_probe_device() + 268 __device_attach_driver() + 524 __device_attach() + 524 bus_probe_device() + 64 deferred_probe_work_func() + 260 process_one_work() + 580 worker_thread() + 1076 kthread() + 332 ret_from_fork() + 16 Signed-off-by: Ning Li Signed-off-by: Yunfei Wang Acked-by: Robin Murphy Reviewed-by: Miles Chen Link: https://lore.kernel.org/r/20220530120748.31733-1-yf.wang@mediatek.com Signed-off-by: Joerg Roedel --- drivers/iommu/dma-iommu.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 9f9d9ba7f376..1910f4f1612b 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -64,6 +64,7 @@ struct iommu_dma_cookie { /* Domain for flush queue callback; NULL if flush queue not in use */ struct iommu_domain *fq_domain; + struct mutex mutex; }; static DEFINE_STATIC_KEY_FALSE(iommu_deferred_attach_enabled); @@ -310,6 +311,7 @@ int iommu_get_dma_cookie(struct iommu_domain *domain) if (!domain->iova_cookie) return -ENOMEM; + mutex_init(&domain->iova_cookie->mutex); return 0; } @@ -560,26 +562,33 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base, } /* start_pfn is always nonzero for an already-initialised domain */ + mutex_lock(&cookie->mutex); if (iovad->start_pfn) { if (1UL << order != iovad->granule || base_pfn != iovad->start_pfn) { pr_warn("Incompatible range for DMA domain\n"); - return -EFAULT; + ret = -EFAULT; + goto done_unlock; } - return 0; + ret = 0; + goto done_unlock; } init_iova_domain(iovad, 1UL << order, base_pfn); ret = iova_domain_init_rcaches(iovad); if (ret) - return ret; + goto done_unlock; /* If the FQ fails we can simply fall back to strict mode */ if (domain->type == IOMMU_DOMAIN_DMA_FQ && iommu_dma_init_fq(domain)) domain->type = IOMMU_DOMAIN_DMA; - return iova_reserve_iommu_regions(dev, domain); + ret = iova_reserve_iommu_regions(dev, domain); + +done_unlock: + mutex_unlock(&cookie->mutex); + return ret; } /** -- cgit v1.2.3-58-ga151