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 --- Documentation/ABI/testing/sysfs-kernel-btf | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-btf (limited to 'Documentation/ABI/testing/sysfs-kernel-btf') diff --git a/Documentation/ABI/testing/sysfs-kernel-btf b/Documentation/ABI/testing/sysfs-kernel-btf new file mode 100644 index 000000000..fe96efdc9 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-btf @@ -0,0 +1,25 @@ +What: /sys/kernel/btf +Date: Aug 2019 +KernelVersion: 5.5 +Contact: bpf@vger.kernel.org +Description: + Contains BTF type information and related data for kernel and + kernel modules. + +What: /sys/kernel/btf/vmlinux +Date: Aug 2019 +KernelVersion: 5.5 +Contact: bpf@vger.kernel.org +Description: + Read-only binary attribute exposing kernel's own BTF type + information with description of all internal kernel types. See + Documentation/bpf/btf.rst for detailed description of format + itself. + +What: /sys/kernel/btf/ +Date: Nov 2020 +KernelVersion: 5.11 +Contact: bpf@vger.kernel.org +Description: + Read-only binary attribute exposing kernel module's BTF type + information as an add-on to the kernel's BTF (/sys/kernel/btf/vmlinux). -- cgit v1.3.1