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 --- drivers/android/binder/trace.rs | 107 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 drivers/android/binder/trace.rs (limited to 'drivers/android/binder/trace.rs') diff --git a/drivers/android/binder/trace.rs b/drivers/android/binder/trace.rs new file mode 100644 index 000000000..06aabb3cc --- /dev/null +++ b/drivers/android/binder/trace.rs @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0 + +// Copyright (C) 2025 Google LLC. + +use crate::transaction::Transaction; + +use core::ptr; + +use kernel::bindings::{rust_binder_transaction, task_struct}; +use kernel::error::Result; +use kernel::ffi::{c_int, c_uint, c_ulong}; +use kernel::task::Task; +use kernel::tracepoint::declare_trace; + +declare_trace! { + unsafe fn binder_ioctl(cmd: c_uint, arg: c_ulong); + unsafe fn binder_ioctl_done(ret: c_int); + unsafe fn binder_read_done(ret: c_int); + unsafe fn binder_write_done(ret: c_int); + unsafe fn binder_wait_for_work(proc_work: bool, transaction_stack: bool, thread_todo: bool); + unsafe fn binder_transaction(reply: bool, t: rust_binder_transaction, thread: *mut task_struct); + unsafe fn binder_transaction_received(t: rust_binder_transaction); + unsafe fn binder_transaction_fd_send(t_debug_id: c_int, fd: c_int, offset: usize); + unsafe fn binder_transaction_fd_recv(t_debug_id: c_int, fd: c_int, offset: usize); + unsafe fn binder_command(cmd: u32); + unsafe fn binder_return(ret: u32); +} + +#[inline] +fn raw_transaction(t: &Transaction) -> rust_binder_transaction { + ptr::from_ref(t).cast_mut().cast() +} + +#[inline] +fn to_errno(ret: Result) -> i32 { + match ret { + Ok(()) => 0, + Err(err) => err.to_errno(), + } +} + +#[inline] +pub(crate) fn trace_ioctl(cmd: u32, arg: usize) { + // SAFETY: Always safe to call. + unsafe { binder_ioctl(cmd, arg as c_ulong) } +} + +#[inline] +pub(crate) fn trace_ioctl_done(ret: Result) { + // SAFETY: Always safe to call. + unsafe { binder_ioctl_done(to_errno(ret)) } +} +#[inline] +pub(crate) fn trace_read_done(ret: Result) { + // SAFETY: Always safe to call. + unsafe { binder_read_done(to_errno(ret)) } +} +#[inline] +pub(crate) fn trace_write_done(ret: Result) { + // SAFETY: Always safe to call. + unsafe { binder_write_done(to_errno(ret)) } +} + +#[inline] +pub(crate) fn trace_wait_for_work(proc_work: bool, transaction_stack: bool, thread_todo: bool) { + // SAFETY: Always safe to call. + unsafe { binder_wait_for_work(proc_work, transaction_stack, thread_todo) } +} + +#[inline] +pub(crate) fn trace_transaction(reply: bool, t: &Transaction, thread: Option<&Task>) { + let thread = match thread { + Some(thread) => thread.as_ptr(), + None => core::ptr::null_mut(), + }; + // SAFETY: The raw transaction is valid for the duration of this call. The thread pointer is + // valid or null. + unsafe { binder_transaction(reply, raw_transaction(t), thread) } +} + +#[inline] +pub(crate) fn trace_transaction_received(t: &Transaction) { + // SAFETY: The raw transaction is valid for the duration of this call. + unsafe { binder_transaction_received(raw_transaction(t)) } +} + +#[inline] +pub(crate) fn trace_transaction_fd_send(t_debug_id: usize, fd: u32, offset: usize) { + // SAFETY: This function is always safe to call. + unsafe { binder_transaction_fd_send(t_debug_id as c_int, fd as c_int, offset) } +} +#[inline] +pub(crate) fn trace_transaction_fd_recv(t_debug_id: usize, fd: u32, offset: usize) { + // SAFETY: This function is always safe to call. + unsafe { binder_transaction_fd_recv(t_debug_id as c_int, fd as c_int, offset) } +} + +#[inline] +pub(crate) fn trace_command(cmd: u32) { + // SAFETY: This function is always safe to call. + unsafe { binder_command(cmd) } +} +#[inline] +pub(crate) fn trace_return(ret: u32) { + // SAFETY: This function is always safe to call. + unsafe { binder_return(ret) } +} -- cgit v1.3.1