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/amdpmf-interface | 73 ++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) create mode 100644 Documentation/ABI/testing/amdpmf-interface (limited to 'Documentation/ABI/testing/amdpmf-interface') diff --git a/Documentation/ABI/testing/amdpmf-interface b/Documentation/ABI/testing/amdpmf-interface new file mode 100644 index 000000000..625f90a01 --- /dev/null +++ b/Documentation/ABI/testing/amdpmf-interface @@ -0,0 +1,73 @@ +What: /dev/amdpmf_interface +Date: June 2026 +KernelVersion: 7.2 +Contact: Shyam Sundar S K +Description: + The AMD Platform Management Framework (PMF) util layer exposes a + minimal user-space interface via a character device for feature + discovery and metrics monitoring. + + When CONFIG_AMD_PMF_UTIL_SUPPORT is enabled, the driver creates + a character device: + + ====================== + /dev/amdpmf_interface + ====================== + + The interface supports a single ioctl: + + ============================ ======================================= + IOCTL Usage + IOCTL_AMD_PMF_POPULATE_DATA User passes a struct amd_pmf_info with + the size field set to sizeof(struct + amd_pmf_info). The driver returns all + available metrics and feature status + in the structure. + ============================ ======================================= + + struct amd_pmf_info layout: + + ======================= ========== ================================ + Field Type Description + size __u64 Structure size for versioning + features_supported __u32 Bitmask of supported features + platform_type __u32 Platform form factor orientation + power_source __u32 AC/DC power source + laptop_placement __u32 Device placement state + lid_state __u32 Lid open/closed status + user_presence __u32 User presence detection + slider_position __u32 Current power slider position + skin_temp __s32 Skin temperature (centidegrees) + gfx_busy __u32 Graphics workload percentage + ambient_light __s32 Ambient light sensor reading + avg_c0_residency __u32 Average C0 state residency + max_c0_residency __u32 Maximum C0 state residency + socket_power __u32 Socket power consumption + bios_input[10] __u32 Custom BIOS input parameters + bios_output[10] __u32 Custom BIOS output parameters + ======================= ========== ================================ + + Feature Support Flags (features_supported bitmask): + + ===================================== ==== ============================= + Flag Bit Description + AMD_PMF_FEAT_AUTO_MODE 0 Auto Mode feature support + AMD_PMF_FEAT_STATIC_POWER_SLIDER 1 Static Power Slider support + AMD_PMF_FEAT_POLICY_BUILDER 2 Policy Builder (Smart PC) + AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_AC 3 Dynamic slider on AC + AMD_PMF_FEAT_DYNAMIC_POWER_SLIDER_DC 4 Dynamic slider on DC + ===================================== ==== ============================= + + Return codes: + + ============= ============================================================ + Return code Description + 0 Success + EINVAL Invalid size or parameter + EFAULT copy_to_user/copy_from_user failures + ENODEV PMF device not available + ENOTTY Unknown ioctl command + ============= ============================================================ + + User-space tools integrating with AMD PMF to discover capabilities and + monitor real-time metrics for thermal and power management validation. -- cgit v1.3.1