From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- include/kvm/iodev.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/kvm/iodev.h (limited to 'include/kvm/iodev.h') diff --git a/include/kvm/iodev.h b/include/kvm/iodev.h new file mode 100644 index 000000000..56619e332 --- /dev/null +++ b/include/kvm/iodev.h @@ -0,0 +1,58 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __KVM_IODEV_H__ +#define __KVM_IODEV_H__ + +#include +#include + +struct kvm_io_device; +struct kvm_vcpu; + +/** + * kvm_io_device_ops are called under kvm slots_lock. + * read and write handlers return 0 if the transaction has been handled, + * or non-zero to have it passed to the next device. + **/ +struct kvm_io_device_ops { + int (*read)(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, + int len, + void *val); + int (*write)(struct kvm_vcpu *vcpu, + struct kvm_io_device *this, + gpa_t addr, + int len, + const void *val); + void (*destructor)(struct kvm_io_device *this); +}; + + +struct kvm_io_device { + const struct kvm_io_device_ops *ops; +}; + +static inline void kvm_iodevice_init(struct kvm_io_device *dev, + const struct kvm_io_device_ops *ops) +{ + dev->ops = ops; +} + +static inline int kvm_iodevice_read(struct kvm_vcpu *vcpu, + struct kvm_io_device *dev, gpa_t addr, + int l, void *v) +{ + return dev->ops->read ? dev->ops->read(vcpu, dev, addr, l, v) + : -EOPNOTSUPP; +} + +static inline int kvm_iodevice_write(struct kvm_vcpu *vcpu, + struct kvm_io_device *dev, gpa_t addr, + int l, const void *v) +{ + return dev->ops->write ? dev->ops->write(vcpu, dev, addr, l, v) + : -EOPNOTSUPP; +} + +#endif /* __KVM_IODEV_H__ */ -- cgit v1.3.1