feat: Sentry native crash backend #1433

mujacica · 2025-10-29T19:54:05Z

Sentry native crash backend
Out-of-process daemon/handler
MacOS/Android/Windows/Linux support
Integration with external crash reporter
IPC/SHM/Signaling multi-platform implementation
Minidump writers for all platforms
In-process option (process_crash function)
Different options for Minidump sizes
Full sentry-codebase integration
Sentry logger integration
Sentry debug-flags integration

mujacica · 2026-01-12T12:27:56Z

mujacica · 2026-01-13T17:54:54Z

src/backends/native/sentry_crash_daemon.c

Extract PE TimeDateStamp from module files on disk and include code_id (timestamp + size) in debug_meta images. This helps Sentry identify Windows PE modules even without full PDB debug info. The code_id format is "{TimeDateStamp:08X}{SizeOfImage:x}" which matches the Windows symbol server convention. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Start stack capture from minimum of SP and FP (FP might be below SP) - Add debug logging for SP, FP, and stack start values - Log GetLastError() when ReadProcessMemory or OpenProcess fails Note: Frame pointer-based unwinding on Windows x64/ARM64 is unreliable since compilers often don't use frame pointers. A proper fix would use StackWalk64 from dbghelp.dll, but this improves diagnostics for now. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Replace frame pointer-based stack walking with StackWalk64 from dbghelp.dll for reliable out-of-process stack unwinding on Windows x64/ARM64. Key changes: - Add walk_stack_with_dbghelp() function for out-of-process unwinding - Use custom ReadMemoryRoutine callback for cross-process memory access - Initialize dbghelp with SymInitialize() for proper PE unwind info access - Works like the inproc backend but for the crashed process This fixes the issue where Windows crash events only had 1 frame because frame pointer-based unwinding doesn't work reliably on x64/ARM64 where compilers often optimize away frame pointers. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Move dbghelp.h include and forward declaration to top of file so the function is declared before it's called in build_stacktrace_for_thread. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

…hreads - Add enrich_frame_with_module_info() to set package and image_addr on frames - Update Linux/Windows thread loops to build stacktraces for all threads - Use thread-specific context for Windows StackWalk64 calls - Fix macOS stack file deletion timing to preserve files for native stacktrace Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Return null stacktrace when frames array is empty (Sentry rejects empty frames) - Only add stacktrace to thread if it contains frames - Use thread-specific ucontext_t for Linux register extraction Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Remove unused thread_id variable from register extraction section (the StackWalk64 section already has its own walk_thread_id). Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

The module capture from /proc/pid/maps was only using the size of the first memory mapping for each module. This caused frame-to-module matching to fail for addresses in later segments (code, data) since those addresses fell outside the incorrectly small module bounds. For example, a PIE binary might have: - First mapping: 0x5500-0x5510 (rodata, offset=0) → size=0x10 - Code mapping: 0x5510-0x5590 (code, offset=0x10) - Data mapping: 0x5590-0x55a0 (data, offset=0x90) Previously we'd set size=0x10, so code addresses like 0x5540 would not match the module. Now we track all mappings and extend the size to cover from base_address to the maximum end address of all segments. This fixes the issue where Linux native backend crashes showed <unknown> for module names in Sentry, while Windows and macOS worked correctly (they use platform APIs that return accurate sizes). Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

The mod->uuid field is uint8_t[] with 1-byte alignment, but GUID structure requires 4-byte alignment. Casting directly to GUID* could cause undefined behavior or incorrect reads on some platforms. Use memcpy to copy bytes into a properly aligned GUID struct before passing to sentry__uuid_from_native(). This fix ensures debug_id is correctly formatted, allowing Sentry to match frames to debug images properly. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Add debug logging to crash daemon: - Log module count before adding debug_meta - Warn when no modules are captured - Log when frames can't be matched to any module Add diagnostic output to E2E tests: - Add get_debug_meta_from_event() helper function - Print debug_meta.images info (count, addresses, sizes) - Print frame info (instruction addresses, symbolication status) This helps diagnose why Windows shows "unknown problem" while Linux shows "missing debug files" - the difference indicates frames aren't being matched to debug images on Windows. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mujacica · 2026-01-16T16:37:38Z

@sentry review

src/backends/native/sentry_crash_ipc.c

The native backend on Windows was causing symbolicator to fail with "internal server error" because it was missing the debug_file field that minidump events include. This prevented proper symbolication. Changes: - Add pdb_name field to sentry_module_info_t struct - Extract PDB filename from PE CodeView debug directory - Set debug_file field on PE images in native crash events - Fix code_id format to use lowercase hex (matching minidump format) The debug_file field is essential for Sentry's symbolicator to know where to look for PDB files when symbolicating Windows crash events. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

The native backend on Windows was causing symbolicator to fail with "internal server error" because: 1. Missing debug_file field that tells symbolicator where to find PDBs 2. code_id format was wrong - timestamp needs 8-digit zero-padding Changes: - Add pdb_name field to sentry_module_info_t struct (Windows-only) - Extract PDB filename from PE CodeView debug directory - Set debug_file field on PE images in native crash events - Fix code_id format: use %08x%x (8-digit padded timestamp + size) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/backends/native/minidump/sentry_minidump_macos.c

- Fix MAX_STACK_SIZE mismatch on macOS (was 64KB, now 512KB like Linux) - Add bounds checks for module_count/num_threads to prevent OOB access - Fix ELF note parsing to use aligned sizes in bounds check - Add bounds validation to Mach-O load command parsing - Fix Memory64 base_rva type to uint64_t per minidump spec Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- Add module_list and memory_list streams to macOS success path (was only writing 3 streams, missing critical symbolication data) - Use platform.mcontext for exception context on macOS (consistent with Linux which uses platform.context) - Fix padding write failure to not corrupt offset tracking (both macOS and Linux now only update offset on success) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/backends/native/sentry_crash_ipc.c

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src/backends/native/minidump/sentry_minidump_linux.c

- Move memset inside shm_exists check to avoid corrupting existing shared memory during re-initialization (fixes daemon attach failure) - Add check for zero aligned sizes in ELF note parsing to prevent infinite loop on 32-bit systems with malformed notes Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

github-actions · 2026-01-20T11:28:33Z

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📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

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bitsandfoxes mentioned this pull request Nov 13, 2025

Custom Sentry Crash Reporter to replace vendored backends #1449

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sentry bot reviewed Jan 13, 2026

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src/backends/native/sentry_crash_daemon.c Show resolved Hide resolved

mujacica added 26 commits January 15, 2026 10:33

Initial implementation

22cc593

Update build structure and daemon

c08fdb4

Updates for Windows support

14acb34

Fix logging

5edcb7d

Fix MacOs builds

02a6d71

Fix Warnings

5395f73

Test fixes

4951eda

Fix linux builds

9c0fd1b

Fix linux/mac modules

a71cf41

Fix concurency

18e5eb4

Fix build errors

1bd917c

Formatting

6a6e5c2

Fix 32bit builds

d5e589d

Fix format

6557ce8

Fix some issues

6a7dc03

Native tests need http/transport

931e568

Fix CMake

95728b6

Fix build

94f3250

Fix errors

d7ef2a6

Fix format

3958e80

Fix style

5d8ba3f

Fix some of the issues

da3e584

Fix format

1f9789c

Moooore fixes

203d113

Debug CI

866b4f0

More debug

f2719fc

mujacica and others added 11 commits January 16, 2026 10:39

Fix Windows build: add forward declaration for walk_stack_with_dbghelp

29dca8a

Move dbghelp.h include and forward declaration to top of file so the function is declared before it's called in build_stacktrace_for_thread. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Fix unused variable warning on Windows ClangCL build

8b3565d

Remove unused thread_id variable from register extraction section (the StackWalk64 section already has its own walk_thread_id). Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

sentry bot reviewed Jan 16, 2026

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src/backends/native/sentry_crash_ipc.c Show resolved Hide resolved

mujacica force-pushed the feat/sentry_native_backend branch from d46d50a to d38b5e1 Compare January 17, 2026 08:10

mujacica marked this pull request as ready for review January 17, 2026 11:50

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More windows fixes + PR fixes

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mujacica force-pushed the feat/sentry_native_backend branch from d33258f to 71ea60d Compare January 20, 2026 10:01

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src/backends/native/minidump/sentry_minidump_linux.c Show resolved Hide resolved

mujacica changed the title ~~(POC) feat: Sentry native crash backend~~ feat: Sentry native crash backend Jan 20, 2026

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