rp2: crash on soft reboot with DMA IRQ enabled and DMA active

Port, board and/or hardware

rp2 / rp2040

MicroPython version

MicroPython v1.27.0 on 2025-12-09; Raspberry Pi Pico with RP2040

Reproduction

Run the following code:

from rp2 import DMA

def dma_in_handler(dma):
    pass 

buf_src = bytearray(20)
buf_in = bytearray(20)

dma_in = DMA()
dma_in_ctrl = dma_in.pack_ctrl(size=0, treq_sel=0)
dma_in.irq(dma_in_handler, False)
dma_in.config(
    read=buf_src,
    write=buf_in,
    count=20,
    ctrl=dma_in_ctrl,
    trigger=True
)

#dma_in.active(False)
#dma_in.irq(None)

print("Hello")

Now attempt to soft-reboot the device (e.g. Ctrl-D on REPL). The device becomes unresponsive and requires a hard reboot.

Calling dma_in.active(False) before exit avoids the problem
Calling dma_in.irq(None) before exit avoids the problem
Removing the treq_sel parameter avoids the problem (presumably because the DMA is then inactive at the time of reboot)

Expected behaviour

No response

Observed behaviour

Device becomes unresponsive over serial after program is run and then MP is soft-rebooted.

Additional Information

No, I've provided everything above.

Code of Conduct

Yes, I agree

Stack trace:

(gdb) bt
#0  SVC_Handler () at /micropython/lib/pico-sdk/src/rp2_common/pico_crt0/crt0.S:334
#1  <signal handler called>
#2  0x1003bf7e in dma_channel_abort (channel=0) at /micropython/lib/pico-sdk/src/rp2_common/hardware_dma/include/hardware/dma.h:763
#3  rp2_dma_close (self_in=0x20005750) at /micropython/ports/rp2/rp2_dma.c:436
#4  0x10015a86 in fun_builtin_1_call (self_in=0x1006114c <rp2_dma_close_obj>, n_args=<optimized out>, n_kw=<optimized out>, args=0x20041f64)
    at /micropython/py/objfun.c:70
#5  0x10020ce2 in mp_call_function_n_kw (fun_in=fun_in@entry=0x1006114c <rp2_dma_close_obj>, n_args=n_args@entry=1, n_kw=n_kw@entry=0, args=args@entry=0x20041f64)
    at /micropython/py/runtime.c:712
#6  0x10020d9c in mp_call_function_1 (fun=fun@entry=0x1006114c <rp2_dma_close_obj>, arg=<optimized out>, arg@entry=0x20005750) at /micropython/py/runtime.c:690
#7  0x1002243e in mp_call_function_1_protected (fun=0x1006114c <rp2_dma_close_obj>, arg=0x20005750) at /micropython/py/runtime_utils.c:33
#8  0x1000c3f4 in gc_sweep_run_finalisers () at /micropython/py/gc.c:606
#9  0x1000c55e in gc_collect_end () at /micropython/py/gc.c:549
#10 0x1000c5a2 in gc_sweep_all () at /micropython/py/gc.c:544
#11 0x1003a684 in main (argc=<optimized out>, argv=<optimized out>) at /micropython/ports/rp2/main.c:282

(gdb) l
431             dma_channel_config config = { .ctrl = 0 };
432             dma_channel_configure(channel, &config, NULL, NULL, 0, false);
433
434             // Abort this channel. Must be done after clearing EN bit in control
435             // register due to errata RP2350-E5.
436             dma_channel_abort(channel); // <------
437
438             // Clean up interrupt handler to ensure garbage collection
439             mp_irq_obj_t *irq = MP_STATE_PORT(rp2_dma_irq_obj[channel]);
440             MP_STATE_PORT(rp2_dma_irq_obj[channel]) = MP_OBJ_NULL;

rp2/rp2_dma: Disable DMA IRQ before clearing handler function.

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rp2: crash on soft reboot with DMA IRQ enabled and DMA active #18765

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rp2: crash on soft reboot with DMA IRQ enabled and DMA active #18765

Description

Port, board and/or hardware

MicroPython version

Reproduction

Expected behaviour

Observed behaviour

Additional Information

Code of Conduct

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agatti commented on Mar 11, 2026

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