coredump: coredump server support #682

etiaro · 2025-08-11T15:56:20Z

Description

Introduces kernel thread that uses messaging to inform coredump server process about crashed processes and provide any data required for creating coredump for post-mortem analysis with GDB.

Motivation and Context

Types of changes

Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to change)
Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

Already covered by automatic testing.
New test added: (add PR link here).
Tested by hand on: ia32-generic-qemu, armv7r5f-zynqmp-qemu, sparcv8leon-generic-qemu

Checklist:

My change requires a change to the documentation.
I have updated the documentation accordingly.
I have added tests to cover my changes.
All new and existing linter checks and tests passed.
My changes generate no new compilation warnings for any of the targets.

Special treatment

This PR needs additional PRs to work (list the PRs, preferably in merge-order).
!syscalls: move signal handling to kernel #670
hal/armvXm: use cpu_context_t as exc_context_t #685
I will merge this PR by myself when appropriate.

gemini-code-assist

Summary of Changes

Hello @etiaro, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a coredump server functionality to the Phoenix-RTOS kernel. Its primary purpose is to capture the state of a crashed process, including its memory segments, threads, and context, to facilitate post-mortem debugging. This is achieved by integrating the coredump mechanism into the kernel's exception and process management systems, ensuring that fatal errors trigger a coredump rather than just halting the system.

Highlights

Coredump Server Implementation: A new coredump server is added, capable of enqueuing crashed processes and providing their memory and thread information upon request.
Enhanced Exception Handling: The kernel's exception handlers across various architectures are updated to initiate a coredump sequence instead of simply halting the CPU on fatal exceptions.
Process and Thread Management Integration: Core process and thread management routines are modified to support the coredump lifecycle, including marking processes for coredump, handling thread termination during coredump, and managing memory deallocation.
Build System Updates: The build system is updated to compile and link the new coredump server components into the kernel.
Context and Relocation Handling: Improvements are made to how CPU contexts are saved and restored, and relocation information for processes (especially for NOMMU builds) is now accessible for coredump purposes.

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Code Review

This pull request introduces coredump server support, a significant feature involving extensive changes across exception handling, process management, and thread lifecycle. The core logic is implemented in the new coredump module. While the overall approach is sound, I've identified several critical issues, including potential NULL pointer dereferences and a memory leak in proc_join. I've also provided suggestions to improve robustness and fix bugs in the coredump data handling. Please address these points to ensure the stability of this new functionality.

coredump/coredump.c

proc/threads.c

coredump/coredump.c

JIRA: RTOS-1062

coredump/coredump.c

julianuziemblo · 2025-10-31T08:40:52Z

proc/msg-nommu.c

 	thread_t *sender;
 	spinlock_ctx_t sc;

 	p = proc_portGet(port);
 	if (p == NULL) {
 		return -EINVAL;
 	}

 	sender = proc_current();

 	kmsg.msg = msg;
-	kmsg.src = sender->process;
+	kmsg.src = senderProc;
 	kmsg.threads = NULL;
 	kmsg.state = msg_waiting;

 	kmsg.msg->pid = (sender->process != NULL) ? process_getPid(sender->process) : 0;
 	kmsg.msg->priority = sender->priority;


shouldn't this also be just senderProc instead of sender->proc? It seems that calling it for different process might give the msg wrong pid and priority

I agree that the naming is really confusing here.
Primary objective of this modification was to send data from senderProc's address space (for MMU targets, here it doesn't have much effect).
The messaging itself is handled by sender (proc_current()), so in my opinion pid and priority should remain as it is.

That is probably not a great design choice, I'll try to change this function parameter to source map instead of process to show more directly what it does.

julianuziemblo · 2025-10-31T08:41:27Z

proc/msg.c

 	thread_t *sender;
 	spinlock_ctx_t sc;

 	/* TODO - check if msg pointer belongs to user vm_map */
 	if (msg == NULL) {
 		return -EINVAL;
 	}

 	p = proc_portGet(port);
 	if (p == NULL) {
 		return -EINVAL;
 	}

 	sender = proc_current();

 	hal_memcpy(&kmsg.msg, msg, sizeof(msg_t));
-	kmsg.src = sender->process;
+	kmsg.src = senderProc;
 	kmsg.threads = NULL;
 	kmsg.state = msg_waiting;

 	kmsg.msg.pid = (sender->process != NULL) ? process_getPid(sender->process) : 0;
 	kmsg.msg.priority = sender->priority;


same here about senderProc and sender->proc

proc/process.h

coredump/coredump.c

* add proc_sendFromMap to send messages with data from given map * introduce include/coredump.h with coredump server messages structures * introduce coredump thread with queue of crashed threads to dump * introduce proc_crash function that sets up thread for coredumping and kills the process * delay kstack kfree to ghost removal so that thread context is available during coredumping * trigger coredump on termination by standard set of signals JIRA: RTOS-1054

JIRA: RTOS-1054

etiaro changed the title ~~Etiaro/coredump server~~ coredump: coredump server support Aug 11, 2025

gemini-code-assist bot reviewed Aug 11, 2025

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etiaro force-pushed the etiaro/coredump-server branch 3 times, most recently from 5660cd1 to 194e1b9 Compare August 12, 2025 15:19

This was referenced Aug 12, 2025

[DO NOT MERGE] Introduce coredump server phoenix-rtos/phoenix-rtos-project#1370

Draft

Introduce coredump server phoenix-rtos/phoenix-rtos-utils#242

Open

etiaro force-pushed the etiaro/coredump-server branch 4 times, most recently from 1ec9788 to 4634bcc Compare August 13, 2025 12:53

etiaro marked this pull request as ready for review August 13, 2025 12:53

etiaro requested review from Darchiv, agkaminski, lukileczo and nalajcie August 13, 2025 12:55

etiaro force-pushed the etiaro/kernel-sighandlers branch from f7f2833 to 1089083 Compare August 18, 2025 13:04

etiaro force-pushed the etiaro/coredump-server branch 4 times, most recently from 448164a to 29d3166 Compare August 22, 2025 12:45

etiaro force-pushed the etiaro/kernel-sighandlers branch from 1089083 to 4b21ec0 Compare August 22, 2025 12:45

This was referenced Aug 28, 2025

Add coredump server to -multi devices phoenix-rtos/phoenix-rtos-devices#575

Open

libcoredumpsrv: introduction of coredumping phoenix-rtos/phoenix-rtos-corelibs#57

Open

etiaro force-pushed the etiaro/kernel-sighandlers branch from 4b21ec0 to df5951b Compare October 17, 2025 10:25

process: save reloc array in process_t on NOMMU

5d331c8

JIRA: RTOS-1062

etiaro force-pushed the etiaro/coredump-server branch from 29d3166 to 301c469 Compare October 20, 2025 16:01

julianuziemblo reviewed Oct 31, 2025

View reviewed changes

etiaro force-pushed the etiaro/coredump-server branch from 301c469 to 14f63ce Compare November 4, 2025 16:49

etiaro force-pushed the etiaro/coredump-server branch from 14f63ce to 7f22143 Compare November 4, 2025 16:57

etiaro added 2 commits November 4, 2025 18:40

hal: call proc_crash in default and fatal exception handlers

28cea5a

JIRA: RTOS-1054

etiaro force-pushed the etiaro/coredump-server branch from 7f22143 to 28cea5a Compare November 4, 2025 17:41

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etiaro commented Aug 11, 2025 •

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Description

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Types of changes

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Checklist:

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etiaro commented Aug 11, 2025 •

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