CVE-2025-71162

In the Linux kernel, the following vulnerability has been resolved:

dmaengine: tegra-adma: Fix use-after-free

A use-after-free bug exists in the Tegra ADMA driver when audio streams

are terminated, particularly during XRUN conditions. The issue occurs

when the DMA buffer is freed by tegra_adma_terminate_all() before the

vchan completion tasklet finishes accessing it.

The race condition follows this sequence:

1. DMA transfer completes, triggering an interrupt that schedules the

completion tasklet (tasklet has not executed yet)

2. Audio playback stops, calling tegra_adma_terminate_all() which

frees the DMA buffer memory via kfree()

3. The scheduled tasklet finally executes, calling vchan_complete()

which attempts to access the already-freed memory

Since tasklets can execute at any time after being scheduled, there is

no guarantee that the buffer will remain valid when vchan_complete()

runs.

Fix this by properly synchronizing the virtual channel completion:

- Calling vchan_terminate_vdesc() in tegra_adma_stop() to mark the

descriptors as terminated instead of freeing the descriptor.

- Add the callback tegra_adma_synchronize() that calls

vchan_synchronize() which kills any pending tasklets and frees any

terminated descriptors.

Crash logs:

[ 337.427523] BUG: KASAN: use-after-free in vchan_complete+0x124/0x3b0

[ 337.427544] Read of size 8 at addr ffff000132055428 by task swapper/0/0

[ 337.427562] Call trace:

[ 337.427564] dump_backtrace+0x0/0x320

[ 337.427571] show_stack+0x20/0x30

[ 337.427575] dump_stack_lvl+0x68/0x84

[ 337.427584] print_address_description.constprop.0+0x74/0x2b8

[ 337.427590] kasan_report+0x1f4/0x210

[ 337.427598] __asan_load8+0xa0/0xd0

[ 337.427603] vchan_complete+0x124/0x3b0

[ 337.427609] tasklet_action_common.constprop.0+0x190/0x1d0

[ 337.427617] tasklet_action+0x30/0x40

[ 337.427623] __do_softirq+0x1a0/0x5c4

[ 337.427628] irq_exit+0x110/0x140

[ 337.427633] handle_domain_irq+0xa4/0xe0

[ 337.427640] gic_handle_irq+0x64/0x160

[ 337.427644] call_on_irq_stack+0x20/0x4c

[ 337.427649] do_interrupt_handler+0x7c/0x90

[ 337.427654] el1_interrupt+0x30/0x80

[ 337.427659] el1h_64_irq_handler+0x18/0x30

[ 337.427663] el1h_64_irq+0x7c/0x80

[ 337.427667] cpuidle_enter_state+0xe4/0x540

[ 337.427674] cpuidle_enter+0x54/0x80

[ 337.427679] do_idle+0x2e0/0x380

[ 337.427685] cpu_startup_entry+0x2c/0x70

[ 337.427690] rest_init+0x114/0x130

[ 337.427695] arch_call_rest_init+0x18/0x24

[ 337.427702] start_kernel+0x380/0x3b4

[ 337.427706] __primary_switched+0xc0/0xc8