The crash and abort reports printed the last 64 traced calls of the whole
process, so a thread that loops on a traced import (a mutex lock/unlock
pair, a profiler marker) pushes the calls of the faulting thread out of the
report. The ring already keeps the last 65536 calls with their thread.
CopyThreadCallTrace_nid_no_patch returns the most recent calls of one
thread from that ring, oldest first, and both reports (Windows crash and
abort, Linux abort) list up to 32 of them for the reporting thread after
the process-wide list.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A thread that lost the race to write the report passed SIGABRT on straight away, and the default action ended the process while the first thread was still writing. It now waits for the report to finish, polling with nanosleep for at most 2 seconds, before it chains. guest_call_trace_abort_race aborts from two threads at once and checks the whole report; it failed 35 times in 50 without the wait. Reported by jotitadev.
The SIGABRT handler used stdio and dladdr, so an abort raised while another thread held the stderr lock or the loader lock hung instead of ending. The report is now formatted into a stack buffer and written with write(2). Callers are named from a module list taken with dl_iterate_phdr when imports are traced, and import counts are read without a lock from a fixed record array. The abort test now holds the stderr lock in another thread, which timed out before this change.
Build the call tracer for Linux as well as Windows. The thunk area is a
memfd mapped twice, writable and executable, and threads are named by
gettid. Linux has no crash report, so the first traced import installs a
SIGABRT handler that prints the last calls and the most called imports,
then passes the signal on to the previous handler.
guest_call_trace and guest_call_trace_abort now run on Linux too.
TraceImport_nid_no_patch wraps a function of a library named in
APS5_TRACE_CALLS in a thunk that records the import, the thread and
the caller in a ring and counts the call, then jumps to the function.
One target keeps one thunk, so function pointers compare equal. The
crash and abort reports print the last 64 calls and the 32 most called
imports. Nothing calls TraceImport_nid_no_patch yet.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
