From 322ae2420d27fc96d0a8ab1167d7de33671048df Mon Sep 17 00:00:00 2001 From: Abseil Team Date: Tue, 12 Jan 2021 07:36:20 -0800 Subject: Export of internal Abseil changes -- 1609589925459c2c0b2a17912c0d65227f709db9 by Abseil Team : Clarify the "Potential Mutex deadlock" reason message. PiperOrigin-RevId: 351367862 -- 88bf28863db2c2d2d48767c3e4dfab6a48bdff79 by Abseil Team : Print CPU number is fault handler. This CL adds code to print CPU number inside the fault handler. This is only supported on Linux. The CPU number is also a hint only. There is no guarantee that it is indeed the CPU on which a fault happened. PiperOrigin-RevId: 351238373 -- 66a9c8e44b5744fec1ca0d7b8db7e1d50772d9a2 by Samuel Benzaquen : Add better error message for ODR violations of flags. PiperOrigin-RevId: 351197423 -- 6efd1efb341563148dd43255aaa4bf959dfd9554 by Chris Kennelly : Assume bitwise builtins are available on GCC. These are long-standing builtins but are not consistently detected by ABSL_HAVE_BUILTIN. PiperOrigin-RevId: 350814036 GitOrigin-RevId: 1609589925459c2c0b2a17912c0d65227f709db9 Change-Id: Ied3fd2f135187f2c316b403fba45f3bbaea54138 --- absl/debugging/failure_signal_handler.cc | 36 +++++++++++++++++++-------- absl/debugging/failure_signal_handler_test.cc | 6 +++++ 2 files changed, 32 insertions(+), 10 deletions(-) (limited to 'absl/debugging') diff --git a/absl/debugging/failure_signal_handler.cc b/absl/debugging/failure_signal_handler.cc index 5d13bdbb..a9ed6ef9 100644 --- a/absl/debugging/failure_signal_handler.cc +++ b/absl/debugging/failure_signal_handler.cc @@ -21,6 +21,7 @@ #ifdef _WIN32 #include #else +#include #include #endif @@ -219,17 +220,24 @@ static void WriteToStderr(const char* data) { absl::raw_logging_internal::SafeWriteToStderr(data, strlen(data)); } -static void WriteSignalMessage(int signo, void (*writerfn)(const char*)) { - char buf[64]; +static void WriteSignalMessage(int signo, int cpu, + void (*writerfn)(const char*)) { + char buf[96]; + char on_cpu[32] = {0}; + if (cpu != -1) { + snprintf(on_cpu, sizeof(on_cpu), " on cpu %d", cpu); + } const char* const signal_string = debugging_internal::FailureSignalToString(signo); if (signal_string != nullptr && signal_string[0] != '\0') { - snprintf(buf, sizeof(buf), "*** %s received at time=%ld ***\n", + snprintf(buf, sizeof(buf), "*** %s received at time=%ld%s ***\n", signal_string, - static_cast(time(nullptr))); // NOLINT(runtime/int) + static_cast(time(nullptr)), // NOLINT(runtime/int) + on_cpu); } else { - snprintf(buf, sizeof(buf), "*** Signal %d received at time=%ld ***\n", - signo, static_cast(time(nullptr))); // NOLINT(runtime/int) + snprintf(buf, sizeof(buf), "*** Signal %d received at time=%ld%s ***\n", + signo, static_cast(time(nullptr)), // NOLINT(runtime/int) + on_cpu); } writerfn(buf); } @@ -269,10 +277,10 @@ ABSL_ATTRIBUTE_NOINLINE static void WriteStackTrace( // Called by AbslFailureSignalHandler() to write the failure info. It is // called once with writerfn set to WriteToStderr() and then possibly // with writerfn set to the user provided function. -static void WriteFailureInfo(int signo, void* ucontext, +static void WriteFailureInfo(int signo, void* ucontext, int cpu, void (*writerfn)(const char*)) { WriterFnStruct writerfn_struct{writerfn}; - WriteSignalMessage(signo, writerfn); + WriteSignalMessage(signo, cpu, writerfn); WriteStackTrace(ucontext, fsh_options.symbolize_stacktrace, WriterFnWrapper, &writerfn_struct); } @@ -334,6 +342,14 @@ static void AbslFailureSignalHandler(int signo, siginfo_t*, void* ucontext) { } } + // Increase the chance that the CPU we report was the same CPU on which the + // signal was received by doing this as early as possible, i.e. after + // verifying that this is not a recursive signal handler invocation. + int my_cpu = -1; +#ifdef ABSL_HAVE_SCHED_GETCPU + my_cpu = sched_getcpu(); +#endif + #ifdef ABSL_HAVE_ALARM // Set an alarm to abort the program in case this code hangs or deadlocks. if (fsh_options.alarm_on_failure_secs > 0) { @@ -344,12 +360,12 @@ static void AbslFailureSignalHandler(int signo, siginfo_t*, void* ucontext) { #endif // First write to stderr. - WriteFailureInfo(signo, ucontext, WriteToStderr); + WriteFailureInfo(signo, ucontext, my_cpu, WriteToStderr); // Riskier code (because it is less likely to be async-signal-safe) // goes after this point. if (fsh_options.writerfn != nullptr) { - WriteFailureInfo(signo, ucontext, fsh_options.writerfn); + WriteFailureInfo(signo, ucontext, my_cpu, fsh_options.writerfn); } if (fsh_options.call_previous_handler) { diff --git a/absl/debugging/failure_signal_handler_test.cc b/absl/debugging/failure_signal_handler_test.cc index d8283b2f..6a62428b 100644 --- a/absl/debugging/failure_signal_handler_test.cc +++ b/absl/debugging/failure_signal_handler_test.cc @@ -122,6 +122,12 @@ TEST_P(FailureSignalHandlerDeathTest, AbslFatalSignalsWithWriterFn) { "*** ", absl::debugging_internal::FailureSignalToString(signo), " received at "))); + // On platforms where it is possible to get the current CPU, the + // CPU number is also logged. Check that it is present in output. +#if defined(__linux__) + EXPECT_THAT(error_line, testing::HasSubstr(" on cpu ")); +#endif + if (absl::debugging_internal::StackTraceWorksForTest()) { std::getline(error_output, error_line); EXPECT_THAT(error_line, StartsWith("PC: ")); -- cgit v1.2.3