Messages in this thread Patch in this message | | | Date | Thu, 15 Apr 2021 09:00:57 -0000 | From | "tip-bot2 for Jean-Philippe Brucker" <> | Subject | [tip: x86/urgent] x86/dma: Tear down DMA ops on driver unbind |
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The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: 9f8614f5567eb4e38579422d38a1bdfeeb648ffc Gitweb: https://git.kernel.org/tip/9f8614f5567eb4e38579422d38a1bdfeeb648ffc Author: Jean-Philippe Brucker <jean-philippe@linaro.org> AuthorDate: Wed, 14 Apr 2021 10:26:34 +02:00 Committer: Borislav Petkov <bp@suse.de> CommitterDate: Thu, 15 Apr 2021 10:27:29 +02:00
x86/dma: Tear down DMA ops on driver unbind
Since
08a27c1c3ecf ("iommu: Add support to change default domain of an iommu group")
a user can switch a device between IOMMU and direct DMA through sysfs. This doesn't work for AMD IOMMU at the moment because dev->dma_ops is not cleared when switching from a DMA to an identity IOMMU domain. The DMA layer thus attempts to use the dma-iommu ops on an identity domain, causing an oops:
# echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type # echo 0000:00:05.0 > /sys/sys/bus/pci/drivers/e1000e/bind ... BUG: kernel NULL pointer dereference, address: 0000000000000028 ... Call Trace: iommu_dma_alloc e1000e_setup_tx_resources e1000e_open
Implement arch_teardown_dma_ops() on x86 to clear the device's dma_ops pointer during driver unbind.
[ bp: Massage commit message. ]
Fixes: 08a27c1c3ecf ("iommu: Add support to change default domain of an iommu group") Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210414082633.877461-1-jean-philippe@linaro.org --- arch/x86/Kconfig | 1 + arch/x86/kernel/pci-dma.c | 7 +++++++ 2 files changed, 8 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2792879..2c90f8d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -85,6 +85,7 @@ config X86 select ARCH_HAS_STRICT_MODULE_RWX select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE select ARCH_HAS_SYSCALL_WRAPPER + select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_DMA select ARCH_HAS_UBSAN_SANITIZE_ALL select ARCH_HAS_DEBUG_WX select ARCH_HAVE_NMI_SAFE_CMPXCHG diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index de234e7..60a4ec2 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -154,3 +154,10 @@ static void via_no_dac(struct pci_dev *dev) DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_VENDOR_ID_VIA, PCI_ANY_ID, PCI_CLASS_BRIDGE_PCI, 8, via_no_dac); #endif + +#ifdef CONFIG_ARCH_HAS_TEARDOWN_DMA_OPS +void arch_teardown_dma_ops(struct device *dev) +{ + set_dma_ops(dev, NULL); +} +#endif
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