[Diagnostics] Add InProc CrashReport Logging by mdh1418 · Pull Request #128105 · dotnet/runtime

mdh1418 · 2026-05-12T23:23:26Z

This adds a compact text view of the in-proc crash report for mobile, while preserving the existing JSON crash report file output when DOTNET_DbgMiniDumpName is configured.

The compact output is intentionally tombstone-style: it prints process/signal metadata, per-thread frame stacks, a module table, and a footer. It omits data that platform crash reports already provide well, such as registers, memory-near dumps, and memory maps.

On Android, the compact report is emitted to logcat under a dedicated DOTNET_CRASH tag for easy filtering. On iOS, the same compact report is emitted through the existing stderr/minipal log path.

Details

Adds signal-safe formatting helpers shared by the JSON writer and compact log writer.
Adds a compact crash log writer: Android uses DOTNET_CRASH, while non-Android targets write newline-delimited compact report lines through the existing error log path.
Emits compact per-thread managed frame stacks alongside the JSON file writer.
Deduplicates managed modules into a fixed-size module table and references frames by module index.
Adds DOTNET_CrashReportFrameLimitPerThread; default is 32 frames per thread, and 0 disables the compact-log cap.
Keeps the JSON crash report file as the authoritative detailed artifact; the frame cap only limits compact log output.
Enables the in-proc crash reporter for Android and Apple app-model targets (iOS, tvOS, and MacCatalyst), including Apple ucontext_t register extraction.

Android Emulator Validation

Validated on Android x64 emulator with the same crash scenarios as #126916, comparing the console output with the json file.

Unhandled managed exception: compact output and JSON emitted; top frames matched.
Managed FailFast: compact output and JSON emitted; top frames matched.
P/Invoke abort: compact output and JSON emitted; top frames matched.
SIGSEGV: compact output and JSON emitted; top frames matched.
Interleaved managed/native frames via pthread_once: compact output and JSON emitted; top frames matched.

iOS simulator validation

Validated compact console crash-report emission on iossimulator-arm64

All scenarios emitted both:

the on-disk .crashreport.json
the compact .NET Crash Report v1.0.0 console report in the app log

nullref, sigsegv, abort,failfast, unhandled, interleaved, stackoverflow

For every scenario, the console report included the compact header, signal, per-thread blocks, managed frames, and a modules: table. Console thread counts matched the corresponding JSON crash report.

… namespace Moves the async-signal-safe integer formatting helpers and buffer-size constants out of SignalSafeJsonWriter into a shared SignalSafeFormat namespace. The helpers are JSON-agnostic and are needed by both the JSON writer and later compact console output without introducing a sibling dependency. This is intended as a behavior-preserving refactor: JSON writer call sites continue to use the same bounded fixed-buffer formatting logic, just through the shared helper namespace. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Adds SignalSafeConsoleWriter, a bounded line-oriented sink that writes DOTNET_CRASH entries through __android_log_write on Android and newline-terminated stderr lines elsewhere. CreateReport now emits a compact tombstone-style header/footer alongside the existing JSON report path. The JSON header/footer emission is split into helpers, and DbgMiniDumpName becomes optional: when no JSON path is configured, the JSON writer uses a no-op sink while the compact log still runs. PROCGetSignalNameAscii exposes the existing signal-name table in the narrow form used by the compact log. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Adds shared frame-sink plumbing so each walked frame can feed both the JSON writer and the compact console writer. The compact log now emits per-thread headers, managed exception info, managed frame lines with IL offset/token, native frame lines with module offsets, and a marker when no managed frames were reported. Both normal thread enumeration and the synthesized crash-thread fallback use the same console block helpers, keeping per-thread compact-log structure in one place. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…dule-index references Adds ModuleTable, a 64-entry fixed-capacity table keyed by MVID for one crash report. Compact-log frames can refer to modules by short [N] indices, and the footer emits a modules block that maps each index back to the module filename and MVID. If a managed frame's module cannot be stored because the table is full or the GUID is missing, the frame renders the module name inline as (in <name>) instead of using a lossy placeholder. JSON output is unchanged; module indices are only a compact-log representation detail. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Adds DOTNET_CrashReportFrameLimitPerThread, parsed as base 10 with default 32, to cap the number of frames written per thread to the compact log. Setting the value to 0 disables the limit. Frames past the cap are still emitted to the JSON report. The compact log skips only the console frame line, tracks how many frames were omitted for the current thread, and emits an "... +N more frames" summary in the thread footer. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

dotnet-policy-service · 2026-05-12T23:25:07Z

Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag
See info in area-owners.md if you want to be subscribed.

Copilot

Pull request overview

This PR extends CoreCLR’s in-process crash reporting path to emit a compact, signal-safe crash log for mobile scenarios while preserving JSON file output when DOTNET_DbgMiniDumpName is configured.

Changes:

Adds shared signal-safe formatting helpers and a line-oriented compact console/logcat writer.
Refactors in-proc crash report emission into JSON header/footer and compact log sections.
Adds frame limiting and module-table support for compact per-thread stack output.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
`src/coreclr/vm/crashreportstackwalker.cpp`	Allows crash reporting without a dump path and wires frame-limit configuration.
`src/coreclr/pal/src/thread/process.cpp`	Adds ASCII POSIX signal-name helper.
`src/coreclr/pal/src/include/pal/process.h`	Declares the signal-name helper for crash reporting.
`src/coreclr/inc/clrconfigvalues.h`	Adds `CrashReportFrameLimitPerThread` configuration.
`src/coreclr/debug/crashreport/signalsafejsonwriter.h`	Removes formatter declarations now moved to shared helper.
`src/coreclr/debug/crashreport/signalsafejsonwriter.cpp`	Uses shared signal-safe formatting helpers.
`src/coreclr/debug/crashreport/signalsafeformat.h`	Adds shared bounded integer formatting declarations.
`src/coreclr/debug/crashreport/signalsafeformat.cpp`	Implements shared bounded integer formatting.
`src/coreclr/debug/crashreport/signalsafeconsolewriter.h`	Adds compact line-oriented crash log writer interface.
`src/coreclr/debug/crashreport/signalsafeconsolewriter.cpp`	Implements Android logcat / stderr compact crash log output.
`src/coreclr/debug/crashreport/inproccrashreporter.h`	Adds compact output helpers and frame-limit state.
`src/coreclr/debug/crashreport/inproccrashreporter.cpp`	Emits compact crash logs alongside JSON reporting.
`src/coreclr/debug/crashreport/CMakeLists.txt`	Includes new crash-report helper source files.

Preserve the fatal stack-overflow reason across the PAL abort path so the in-proc crash reporter does not try to run the generic managed thread walk on the constrained stack-overflow handler path. Reuse the runtime stack-overflow helper thread's compressed managed stack trace and render it directly in the in-proc crash report JSON and compact log output. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Move reporter-owned temporary buffers and VM callback scratch out of crash-time stack locals so fatal signal paths do not depend on large stack allocations for report paths, method names, module IDs, and thread enumeration state. Keep the existing one-report-at-a-time guard as the synchronization boundary for the reusable scratch storage. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Ensure full and truncated compact crash log lines end with a newline on non-Android sinks instead of relying on later writes for line framing. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Keep signal-name formatting in the crash reporter instead of exposing a PAL helper only used by this path. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Separate report-level begin/end flow from per-thread formatting helpers so JSON and compact console lifecycles are easier to review independently. Keep behavior unchanged while centralizing JSON finalization in EndJsonReport. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Store only Module handles in the compact module table and resolve name/GUID when formatting the modules footer. Preserve the existing per-frame JSON module metadata while making the compact console table follow the review feedback. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Remove the dead JSON-only frame callback and route walked frames through one JSON-plus-console emission path. Also preserve token/IL identity when method names are unavailable and drop unused siginfo plumbing. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

mdh1418 and others added 5 commits May 12, 2026 01:53

mdh1418 requested review from Copilot and lateralusX May 12, 2026 23:23

Copilot started reviewing on behalf of mdh1418 May 12, 2026 23:23 View session

mdh1418 added area-Diagnostics-coreclr os-android os-ios Apple iOS labels May 12, 2026

dotnet-policy-service Bot assigned mdh1418 May 12, 2026

Copilot AI reviewed May 12, 2026

View reviewed changes

Comment thread src/coreclr/debug/crashreport/inproccrashreporter.cpp Outdated

Comment thread src/coreclr/debug/crashreport/signalsafeconsolewriter.cpp Outdated

build-analysis Bot mentioned this pull request May 13, 2026

Unable to pull image from mcr.microsoft.com #117164

Open