probe-rs: jlink: stack overflow on fault, endless calls to `DAPAccess:write_register`

DAPAccess::write_register calls itself on fault, which can in turn fault again, leading to infinite stack overflow.

https://github.com/probe-rs/probe-rs/blob/9a10a0c0c439b64a597c576209164f1f8ad4033b/probe-rs/src/probe/jlink/swd.rs#L737

(... many lines like this..)
#3439 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3440 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3441 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3442 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3443 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3444 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3445 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3446 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3447 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3448 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=0, value=16) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3449 0x0000555555ab3178 in probe_rs::probe::jlink::swd::{{impl}}::write_register<probe_rs::probe::jlink::JLink> (self=0x555555fec830, port=..., address=4, value=3758157296) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/jlink/swd.rs:795
#3450 0x0000555555a7154f in probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface::write_ap_register<probe_rs::architecture::arm::ap::memory_ap::MemoryAP,probe_rs::architecture::arm::ap::memory_ap::TAR,probe_rs::architecture::arm::ap::memory_ap::MemoryAP> (self=0x555555fd74f0, port=..., register=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/communication_interface.rs:422
#3451 0x0000555555a789b1 in probe_rs::architecture::arm::communication_interface::{{impl}}::write_ap_register<probe_rs::architecture::arm::ap::memory_ap::TAR,probe_rs::architecture::arm::ap::memory_ap::MemoryAP> (self=0x555555fd74f0, port=..., register=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/communication_interface.rs:670
#3452 0x0000555555a68e82 in probe_rs::architecture::arm::memory::adi_v5_memory_interface::ADIMemoryInterface<probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface>::write_ap_register<probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface,probe_rs::architecture::arm::ap::memory_ap::TAR> (self=0x555555fd84f0, access_port=..., register=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/memory/adi_v5_memory_interface.rs:191
#3453 0x0000555555a6922a in probe_rs::architecture::arm::memory::adi_v5_memory_interface::ADIMemoryInterface<probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface>::read_word_32<probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface> (self=0x555555fd84f0, access_port=..., address=3758157296) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/memory/adi_v5_memory_interface.rs:231
#3454 0x0000555555a6eb5b in probe_rs::architecture::arm::memory::adi_v5_memory_interface::{{impl}}::read_32<probe_rs::architecture::arm::communication_interface::ArmCommunicationInterface> (self=0x555555fd84f0, ap=..., address=3758157296, data=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/memory/adi_v5_memory_interface.rs:651
#3455 0x0000555555a94e59 in probe_rs::memory::Memory::read_word_32 (self=0x7fffffff5ff8, address=3758157296) at /home/dirbaio/rp/probe-rs/probe-rs/src/memory/mod.rs:113
#3456 0x0000555555a548ab in probe_rs::architecture::arm::core::m0::M0::new (memory=..., state=0x555555fd8701) at /home/dirbaio/rp/probe-rs/probe-rs/src/architecture/arm/core/m0.rs:274
#3457 0x00005555559f05b7 in probe_rs::core::SpecificCoreState::attach_arm (self=0x555555fd8700, state=0x555555fd8708, memory=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/core/mod.rs:307
#3458 0x0000555555a1bad4 in probe_rs::session::ArchitectureInterface::attach (self=0x7fffffff6c70, core=0x555555fd8700, core_state=0x555555fd8708) at /home/dirbaio/rp/probe-rs/probe-rs/src/session.rs:71
#3459 0x0000555555a1bd7f in probe_rs::session::Session::core (self=0x7fffffff6c20, n=0) at /home/dirbaio/rp/probe-rs/probe-rs/src/session.rs:190
#3460 0x00005555556ea10b in probe_rs::session::Session::new<probe_rs::config::target::Target> (probe=..., target=..., attach_method=probe_rs::probe::AttachMethod::Normal) at /home/dirbaio/rp/probe-rs/probe-rs/src/session.rs:112
#3461 0x00005555556aa90b in probe_rs::probe::Probe::attach<probe_rs::config::target::Target> (self=..., target=...) at /home/dirbaio/rp/probe-rs/probe-rs/src/probe/mod.rs:288
#3462 0x0000555555685873 in probe_run::notmain () at /home/dirbaio/rp/probe-run/src/main.rs:317
#3463 0x0000555555681dd9 in probe_run::main () at /home/dirbaio/rp/probe-run/src/main.rs:43

About this issue

Original URL
State: open
Created 3 years ago
Comments: 17 (16 by maintainers)

Commits related to this issue

Merge #1123 1123: jlink: Avoid endless recursion in line_reset r=Yatekii a=Tiwalun When no chip is connected, the J-Link ends up in an endless loop, because no answer is received. To avoid this, we ... — committed to probe-rs/probe-rs by bors[bot] 2 years ago

Most upvoted comments

@noppej I’ve created a new issue for the endless loop in the StackFrameIterator, and I’m working on fixing that now. I’ve split it up, because it seems to be a different issue than the original issue here.

The original issue mentioned here is something in the J-Link implemenation, so I’d like to keep them separate.

Tiwalun on Nov 17, 2021

This issue is unrelated to the vscode debugger pointer loop issues.

This one is something much lower-level, related to the SWD protocol: doing an SWD register write can fault, which sets a “fault” flag. To clear it you have to do another register write, so the “write_register” fn calls itself. Of course the “clear fault” register write isn’t supposed to fault itself, but if it does then it stack overflows 😄

I don’t even know how to reproduce this, it just happened to have.

The fix would be to not recurse infinitely: if fault clearing faults again, abort.

Dirbaio on Jan 20, 2022

I think the problem could be that the StackFrameIterator never finishes, but gets caught trying to unwind the same frame in a loop. This then leads to a stack overflow in the end.

To solve this, we should fix the iterator itself, but it’s probably also a good idea to add a limit to the number of stack frames in the debugger itself. AFAIK VS Code only requests a limited amount anyway.

I will have a go at solving this later today, but if someone wants to, feel free to go ahead.

Tiwalun on Nov 17, 2021

@Tiwalun Ubuntu 21.10 Linux j 5.13.0-21-generic #21-Ubuntu SMP Tue Oct 19 08:59:28 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

jacobrosenthal on Nov 16, 2021