[Lldb-commits] [lldb] [LLDB] Support all the Generic (Negative) SI Codes. (PR #140150)
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lldb-commits at lists.llvm.org
Thu May 15 15:05:04 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-lldb
Author: Jacob Lalonde (Jlalond)
<details>
<summary>Changes</summary>
Recently, I was on an issue that generated a large number of Coredumps, and every time in both LLDB and GDB the signal was just `SIGSEGV`.
This was frustrating because we would expect a `SIGSEGV` to have an address, or ideally even bounds. After some digging I found the `si_code` consistently was -6. With some help from [@<!-- -->cdown](https://github.com/cdown), we found neither LLDB or GDB supports the si_codes sent from [user space](https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/siginfo.h#L185).
Excerpted from the sigaction man page.
```
For a regular signal, the following list shows the values which
can be placed in si_code for any signal, along with the reason
that the signal was generated.
```
For which I added all of the si_codes to every Linux signal. Now for the Coredump that triggered this whole investigation we get the accurate and now very informative summary.
<img width="524" alt="image" src="https://github.com/user-attachments/assets/5149f781-ef21-4491-a077-8fac862fbc20" />
Importantly, I didn't add an equivalent of `siginfo_t` to ELFSigInfo, and I think we should open an issue for this to make a (build) platform agnostic struct of siginfo_t. I'll defer to your expertise @<!-- -->labath and @<!-- -->DavidSpickett
---
Patch is 24.96 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/140150.diff
6 Files Affected:
- (modified) lldb/include/lldb/Target/UnixSignals.h (+4-2)
- (modified) lldb/source/Plugins/Process/Utility/LinuxSignals.cpp (+88-66)
- (modified) lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp (+25-16)
- (modified) lldb/source/Plugins/Process/elf-core/ThreadElfCore.h (+23-15)
- (modified) lldb/source/Target/UnixSignals.cpp (+9-6)
- (modified) lldb/unittests/Signals/UnixSignalsTest.cpp (+9)
``````````diff
diff --git a/lldb/include/lldb/Target/UnixSignals.h b/lldb/include/lldb/Target/UnixSignals.h
index b3605ccefddbe..a1807d69f329b 100644
--- a/lldb/include/lldb/Target/UnixSignals.h
+++ b/lldb/include/lldb/Target/UnixSignals.h
@@ -36,7 +36,9 @@ class UnixSignals {
std::optional<int32_t> code = std::nullopt,
std::optional<lldb::addr_t> addr = std::nullopt,
std::optional<lldb::addr_t> lower = std::nullopt,
- std::optional<lldb::addr_t> upper = std::nullopt) const;
+ std::optional<lldb::addr_t> upper = std::nullopt,
+ std::optional<uint32_t> pid = std::nullopt,
+ std::optional<uint32_t> uid = std::nullopt) const;
bool SignalIsValid(int32_t signo) const;
@@ -105,7 +107,7 @@ class UnixSignals {
llvm::StringRef description,
llvm::StringRef alias = llvm::StringRef());
- enum SignalCodePrintOption { None, Address, Bounds };
+ enum SignalCodePrintOption { None, Address, Bounds, Sender };
// Instead of calling this directly, use a ADD_SIGCODE macro to get compile
// time checks when on the native platform.
diff --git a/lldb/source/Plugins/Process/Utility/LinuxSignals.cpp b/lldb/source/Plugins/Process/Utility/LinuxSignals.cpp
index 9c4fe55147a28..76c32e376eb4b 100644
--- a/lldb/source/Plugins/Process/Utility/LinuxSignals.cpp
+++ b/lldb/source/Plugins/Process/Utility/LinuxSignals.cpp
@@ -38,6 +38,28 @@
#define ADD_SIGCODE(signal_name, signal_value, code_name, code_value, ...) \
AddSignalCode(signal_value, code_value, __VA_ARGS__)
#endif /* if defined(__linux__) && !defined(__mips__) */
+// See siginfo.h in the Linux Kernel, these codes can be sent for any signal.
+#define ADD_LINUX_SIGNAL(signo, name, ...) \
+ AddSignal(signo, name, __VA_ARGS__); \
+ ADD_SIGCODE(signo, signo, SI_QUEUE, -1, "sent by sigqueue", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_TIMER, -2, "sent by timer expiration", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_MESGQ, -3, \
+ "sent by real time mesq state change", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_ASYNCIO, -4, "sent by AIO completion", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_SIGIO, -5, "sent by queued SIGIO", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_TKILL, -6, "sent by tkill system call", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_DETHREAD, -7, \
+ "sent by execve() killing subsidiary threads", \
+ SignalCodePrintOption::Sender); \
+ ADD_SIGCODE(signo, signo, SI_ASYNCNL, -60, \
+ "sent by glibc async name lookup completion", \
+ SignalCodePrintOption::Sender);
using namespace lldb_private;
@@ -46,13 +68,13 @@ LinuxSignals::LinuxSignals() : UnixSignals() { Reset(); }
void LinuxSignals::Reset() {
m_signals.clear();
// clang-format off
- // SIGNO NAME SUPPRESS STOP NOTIFY DESCRIPTION
- // ====== ============== ======== ====== ====== ===================================================
- AddSignal(1, "SIGHUP", false, true, true, "hangup");
- AddSignal(2, "SIGINT", true, true, true, "interrupt");
- AddSignal(3, "SIGQUIT", false, true, true, "quit");
+ // SIGNO NAME SUPPRESS STOP NOTIFY DESCRIPTION
+ // ====== ============== ======== ====== ====== ===================================================
+ ADD_LINUX_SIGNAL(1, "SIGHUP", false, true, true, "hangup");
+ ADD_LINUX_SIGNAL(2, "SIGINT", true, true, true, "interrupt");
+ ADD_LINUX_SIGNAL(3, "SIGQUIT", false, true, true, "quit");
- AddSignal(4, "SIGILL", false, true, true, "illegal instruction");
+ ADD_LINUX_SIGNAL(4, "SIGILL", false, true, true, "illegal instruction");
ADD_SIGCODE(SIGILL, 4, ILL_ILLOPC, 1, "illegal opcode");
ADD_SIGCODE(SIGILL, 4, ILL_ILLOPN, 2, "illegal operand");
ADD_SIGCODE(SIGILL, 4, ILL_ILLADR, 3, "illegal addressing mode");
@@ -62,15 +84,15 @@ void LinuxSignals::Reset() {
ADD_SIGCODE(SIGILL, 4, ILL_COPROC, 7, "coprocessor error");
ADD_SIGCODE(SIGILL, 4, ILL_BADSTK, 8, "internal stack error");
- AddSignal(5, "SIGTRAP", true, true, true, "trace trap (not reset when caught)");
- AddSignal(6, "SIGABRT", false, true, true, "abort()/IOT trap", "SIGIOT");
+ ADD_LINUX_SIGNAL(5, "SIGTRAP", true, true, true, "trace trap (not reset when caught)");
+ ADD_LINUX_SIGNAL(6, "SIGABRT", false, true, true, "abort()/IOT trap", "SIGIOT");
- AddSignal(7, "SIGBUS", false, true, true, "bus error");
+ ADD_LINUX_SIGNAL(7, "SIGBUS", false, true, true, "bus error");
ADD_SIGCODE(SIGBUS, 7, BUS_ADRALN, 1, "illegal alignment");
ADD_SIGCODE(SIGBUS, 7, BUS_ADRERR, 2, "illegal address");
ADD_SIGCODE(SIGBUS, 7, BUS_OBJERR, 3, "hardware error");
- AddSignal(8, "SIGFPE", false, true, true, "floating point exception");
+ ADD_LINUX_SIGNAL(8, "SIGFPE", false, true, true, "floating point exception");
ADD_SIGCODE(SIGFPE, 8, FPE_INTDIV, 1, "integer divide by zero");
ADD_SIGCODE(SIGFPE, 8, FPE_INTOVF, 2, "integer overflow");
ADD_SIGCODE(SIGFPE, 8, FPE_FLTDIV, 3, "floating point divide by zero");
@@ -80,10 +102,10 @@ void LinuxSignals::Reset() {
ADD_SIGCODE(SIGFPE, 8, FPE_FLTINV, 7, "floating point invalid operation");
ADD_SIGCODE(SIGFPE, 8, FPE_FLTSUB, 8, "subscript out of range");
- AddSignal(9, "SIGKILL", false, true, true, "kill");
- AddSignal(10, "SIGUSR1", false, true, true, "user defined signal 1");
+ ADD_LINUX_SIGNAL(9, "SIGKILL", false, true, true, "kill");
+ ADD_LINUX_SIGNAL(10, "SIGUSR1", false, true, true, "user defined signal 1");
- AddSignal(11, "SIGSEGV", false, true, true, "segmentation violation");
+ ADD_LINUX_SIGNAL(11, "SIGSEGV", false, true, true, "segmentation violation");
ADD_SIGCODE(SIGSEGV, 11, SEGV_MAPERR, 1, "address not mapped to object", SignalCodePrintOption::Address);
ADD_SIGCODE(SIGSEGV, 11, SEGV_ACCERR, 2, "invalid permissions for mapped object", SignalCodePrintOption::Address);
ADD_SIGCODE(SIGSEGV, 11, SEGV_BNDERR, 3, "failed address bounds checks", SignalCodePrintOption::Bounds);
@@ -94,58 +116,58 @@ void LinuxSignals::Reset() {
// codes. One way to get this is via unaligned SIMD loads. Treat it as invalid address.
ADD_SIGCODE(SIGSEGV, 11, SI_KERNEL, 0x80, "invalid address", SignalCodePrintOption::Address);
- AddSignal(12, "SIGUSR2", false, true, true, "user defined signal 2");
- AddSignal(13, "SIGPIPE", false, true, true, "write to pipe with reading end closed");
- AddSignal(14, "SIGALRM", false, false, false, "alarm");
- AddSignal(15, "SIGTERM", false, true, true, "termination requested");
- AddSignal(16, "SIGSTKFLT", false, true, true, "stack fault");
- AddSignal(17, "SIGCHLD", false, false, true, "child status has changed", "SIGCLD");
- AddSignal(18, "SIGCONT", false, false, true, "process continue");
- AddSignal(19, "SIGSTOP", true, true, true, "process stop");
- AddSignal(20, "SIGTSTP", false, true, true, "tty stop");
- AddSignal(21, "SIGTTIN", false, true, true, "background tty read");
- AddSignal(22, "SIGTTOU", false, true, true, "background tty write");
- AddSignal(23, "SIGURG", false, true, true, "urgent data on socket");
- AddSignal(24, "SIGXCPU", false, true, true, "CPU resource exceeded");
- AddSignal(25, "SIGXFSZ", false, true, true, "file size limit exceeded");
- AddSignal(26, "SIGVTALRM", false, true, true, "virtual time alarm");
- AddSignal(27, "SIGPROF", false, false, false, "profiling time alarm");
- AddSignal(28, "SIGWINCH", false, true, true, "window size changes");
- AddSignal(29, "SIGIO", false, true, true, "input/output ready/Pollable event", "SIGPOLL");
- AddSignal(30, "SIGPWR", false, true, true, "power failure");
- AddSignal(31, "SIGSYS", false, true, true, "invalid system call");
- AddSignal(32, "SIG32", false, false, false, "threading library internal signal 1");
- AddSignal(33, "SIG33", false, false, false, "threading library internal signal 2");
- AddSignal(34, "SIGRTMIN", false, false, false, "real time signal 0");
- AddSignal(35, "SIGRTMIN+1", false, false, false, "real time signal 1");
- AddSignal(36, "SIGRTMIN+2", false, false, false, "real time signal 2");
- AddSignal(37, "SIGRTMIN+3", false, false, false, "real time signal 3");
- AddSignal(38, "SIGRTMIN+4", false, false, false, "real time signal 4");
- AddSignal(39, "SIGRTMIN+5", false, false, false, "real time signal 5");
- AddSignal(40, "SIGRTMIN+6", false, false, false, "real time signal 6");
- AddSignal(41, "SIGRTMIN+7", false, false, false, "real time signal 7");
- AddSignal(42, "SIGRTMIN+8", false, false, false, "real time signal 8");
- AddSignal(43, "SIGRTMIN+9", false, false, false, "real time signal 9");
- AddSignal(44, "SIGRTMIN+10", false, false, false, "real time signal 10");
- AddSignal(45, "SIGRTMIN+11", false, false, false, "real time signal 11");
- AddSignal(46, "SIGRTMIN+12", false, false, false, "real time signal 12");
- AddSignal(47, "SIGRTMIN+13", false, false, false, "real time signal 13");
- AddSignal(48, "SIGRTMIN+14", false, false, false, "real time signal 14");
- AddSignal(49, "SIGRTMIN+15", false, false, false, "real time signal 15");
- AddSignal(50, "SIGRTMAX-14", false, false, false, "real time signal 16"); // switching to SIGRTMAX-xxx to match "kill -l" output
- AddSignal(51, "SIGRTMAX-13", false, false, false, "real time signal 17");
- AddSignal(52, "SIGRTMAX-12", false, false, false, "real time signal 18");
- AddSignal(53, "SIGRTMAX-11", false, false, false, "real time signal 19");
- AddSignal(54, "SIGRTMAX-10", false, false, false, "real time signal 20");
- AddSignal(55, "SIGRTMAX-9", false, false, false, "real time signal 21");
- AddSignal(56, "SIGRTMAX-8", false, false, false, "real time signal 22");
- AddSignal(57, "SIGRTMAX-7", false, false, false, "real time signal 23");
- AddSignal(58, "SIGRTMAX-6", false, false, false, "real time signal 24");
- AddSignal(59, "SIGRTMAX-5", false, false, false, "real time signal 25");
- AddSignal(60, "SIGRTMAX-4", false, false, false, "real time signal 26");
- AddSignal(61, "SIGRTMAX-3", false, false, false, "real time signal 27");
- AddSignal(62, "SIGRTMAX-2", false, false, false, "real time signal 28");
- AddSignal(63, "SIGRTMAX-1", false, false, false, "real time signal 29");
- AddSignal(64, "SIGRTMAX", false, false, false, "real time signal 30");
+ ADD_LINUX_SIGNAL(12, "SIGUSR2", false, true, true, "user defined signal 2");
+ ADD_LINUX_SIGNAL(13, "SIGPIPE", false, true, true, "write to pipe with reading end closed");
+ ADD_LINUX_SIGNAL(14, "SIGALRM", false, false, false, "alarm");
+ ADD_LINUX_SIGNAL(15, "SIGTERM", false, true, true, "termination requested");
+ ADD_LINUX_SIGNAL(16, "SIGSTKFLT", false, true, true, "stack fault");
+ ADD_LINUX_SIGNAL(17, "SIGCHLD", false, false, true, "child status has changed", "SIGCLD");
+ ADD_LINUX_SIGNAL(18, "SIGCONT", false, false, true, "process continue");
+ ADD_LINUX_SIGNAL(19, "SIGSTOP", true, true, true, "process stop");
+ ADD_LINUX_SIGNAL(20, "SIGTSTP", false, true, true, "tty stop");
+ ADD_LINUX_SIGNAL(21, "SIGTTIN", false, true, true, "background tty read");
+ ADD_LINUX_SIGNAL(22, "SIGTTOU", false, true, true, "background tty write");
+ ADD_LINUX_SIGNAL(23, "SIGURG", false, true, true, "urgent data on socket");
+ ADD_LINUX_SIGNAL(24, "SIGXCPU", false, true, true, "CPU resource exceeded");
+ ADD_LINUX_SIGNAL(25, "SIGXFSZ", false, true, true, "file size limit exceeded");
+ ADD_LINUX_SIGNAL(26, "SIGVTALRM", false, true, true, "virtual time alarm");
+ ADD_LINUX_SIGNAL(27, "SIGPROF", false, false, false, "profiling time alarm");
+ ADD_LINUX_SIGNAL(28, "SIGWINCH", false, true, true, "window size changes");
+ ADD_LINUX_SIGNAL(29, "SIGIO", false, true, true, "input/output ready/Pollable event", "SIGPOLL");
+ ADD_LINUX_SIGNAL(30, "SIGPWR", false, true, true, "power failure");
+ ADD_LINUX_SIGNAL(31, "SIGSYS", false, true, true, "invalid system call");
+ ADD_LINUX_SIGNAL(32, "SIG32", false, false, false, "threading library internal signal 1");
+ ADD_LINUX_SIGNAL(33, "SIG33", false, false, false, "threading library internal signal 2");
+ ADD_LINUX_SIGNAL(34, "SIGRTMIN", false, false, false, "real time signal 0");
+ ADD_LINUX_SIGNAL(35, "SIGRTMIN+1", false, false, false, "real time signal 1");
+ ADD_LINUX_SIGNAL(36, "SIGRTMIN+2", false, false, false, "real time signal 2");
+ ADD_LINUX_SIGNAL(37, "SIGRTMIN+3", false, false, false, "real time signal 3");
+ ADD_LINUX_SIGNAL(38, "SIGRTMIN+4", false, false, false, "real time signal 4");
+ ADD_LINUX_SIGNAL(39, "SIGRTMIN+5", false, false, false, "real time signal 5");
+ ADD_LINUX_SIGNAL(40, "SIGRTMIN+6", false, false, false, "real time signal 6");
+ ADD_LINUX_SIGNAL(41, "SIGRTMIN+7", false, false, false, "real time signal 7");
+ ADD_LINUX_SIGNAL(42, "SIGRTMIN+8", false, false, false, "real time signal 8");
+ ADD_LINUX_SIGNAL(43, "SIGRTMIN+9", false, false, false, "real time signal 9");
+ ADD_LINUX_SIGNAL(44, "SIGRTMIN+10", false, false, false, "real time signal 10");
+ ADD_LINUX_SIGNAL(45, "SIGRTMIN+11", false, false, false, "real time signal 11");
+ ADD_LINUX_SIGNAL(46, "SIGRTMIN+12", false, false, false, "real time signal 12");
+ ADD_LINUX_SIGNAL(47, "SIGRTMIN+13", false, false, false, "real time signal 13");
+ ADD_LINUX_SIGNAL(48, "SIGRTMIN+14", false, false, false, "real time signal 14");
+ ADD_LINUX_SIGNAL(49, "SIGRTMIN+15", false, false, false, "real time signal 15");
+ ADD_LINUX_SIGNAL(50, "SIGRTMAX-14", false, false, false, "real time signal 16"); // switching to SIGRTMAX-xxx to match "kill -l" output
+ ADD_LINUX_SIGNAL(51, "SIGRTMAX-13", false, false, false, "real time signal 17");
+ ADD_LINUX_SIGNAL(52, "SIGRTMAX-12", false, false, false, "real time signal 18");
+ ADD_LINUX_SIGNAL(53, "SIGRTMAX-11", false, false, false, "real time signal 19");
+ ADD_LINUX_SIGNAL(54, "SIGRTMAX-10", false, false, false, "real time signal 20");
+ ADD_LINUX_SIGNAL(55, "SIGRTMAX-9", false, false, false, "real time signal 21");
+ ADD_LINUX_SIGNAL(56, "SIGRTMAX-8", false, false, false, "real time signal 22");
+ ADD_LINUX_SIGNAL(57, "SIGRTMAX-7", false, false, false, "real time signal 23");
+ ADD_LINUX_SIGNAL(58, "SIGRTMAX-6", false, false, false, "real time signal 24");
+ ADD_LINUX_SIGNAL(59, "SIGRTMAX-5", false, false, false, "real time signal 25");
+ ADD_LINUX_SIGNAL(60, "SIGRTMAX-4", false, false, false, "real time signal 26");
+ ADD_LINUX_SIGNAL(61, "SIGRTMAX-3", false, false, false, "real time signal 27");
+ ADD_LINUX_SIGNAL(62, "SIGRTMAX-2", false, false, false, "real time signal 28");
+ ADD_LINUX_SIGNAL(63, "SIGRTMAX-1", false, false, false, "real time signal 29");
+ ADD_LINUX_SIGNAL(64, "SIGRTMAX", false, false, false, "real time signal 30");
// clang-format on
}
diff --git a/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp b/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp
index a0cd0ee5025bd..907e009bc7b80 100644
--- a/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp
+++ b/lldb/source/Plugins/Process/elf-core/ThreadElfCore.cpp
@@ -584,22 +584,26 @@ Status ELFLinuxSigInfo::Parse(const DataExtractor &data, const ArchSpec &arch,
// 64b ELF have a 4 byte pad.
if (data.GetAddressByteSize() == 8)
offset += 4;
- // Not every stop signal has a valid address, but that will get resolved in
- // the unix_signals.GetSignalDescription() call below.
- if (unix_signals.GetShouldStop(si_signo)) {
+
+ if (si_code < 0) {
+ sifields.kill.pid = data.GetU32(&offset);
+ sifields.kill.uid = data.GetU32(&offset);
+ } else if (unix_signals.GetShouldStop(si_signo)) {
+ // Not every stop signal has a valid address, but that will get resolved in
+ // the unix_signals.GetSignalDescription() call below.
// Instead of memcpy we call all these individually as the extractor will
// handle endianness for us.
- sigfault.si_addr = data.GetAddress(&offset);
- sigfault.si_addr_lsb = data.GetU16(&offset);
- if (data.GetByteSize() - offset >= sizeof(sigfault.bounds)) {
- sigfault.bounds._addr_bnd._lower = data.GetAddress(&offset);
- sigfault.bounds._addr_bnd._upper = data.GetAddress(&offset);
- sigfault.bounds._pkey = data.GetU32(&offset);
+ sifields.sigfault.si_addr = data.GetAddress(&offset);
+ sifields.sigfault.si_addr_lsb = data.GetU16(&offset);
+ if (data.GetByteSize() - offset >= sizeof(sifields.sigfault.bounds)) {
+ sifields.sigfault.bounds._addr_bnd._lower = data.GetAddress(&offset);
+ sifields.sigfault.bounds._addr_bnd._upper = data.GetAddress(&offset);
+ sifields.sigfault.bounds._pkey = data.GetU32(&offset);
} else {
// Set these to 0 so we don't use bogus data for the description.
- sigfault.bounds._addr_bnd._lower = 0;
- sigfault.bounds._addr_bnd._upper = 0;
- sigfault.bounds._pkey = 0;
+ sifields.sigfault.bounds._addr_bnd._lower = 0;
+ sifields.sigfault.bounds._addr_bnd._upper = 0;
+ sifields.sigfault.bounds._pkey = 0;
}
}
@@ -609,13 +613,18 @@ Status ELFLinuxSigInfo::Parse(const DataExtractor &data, const ArchSpec &arch,
std::string ELFLinuxSigInfo::GetDescription(
const lldb_private::UnixSignals &unix_signals) const {
if (unix_signals.GetShouldStop(si_signo) && note_type == eNT_SIGINFO) {
- if (sigfault.bounds._addr_bnd._upper != 0)
+ if (si_code < 0)
+ return unix_signals.GetSignalDescription(
+ si_signo, si_code, std::nullopt, std::nullopt, std::nullopt,
+ sifields.kill.pid, sifields.kill.uid);
+ else if (sifields.sigfault.bounds._addr_bnd._upper != 0)
return unix_signals.GetSignalDescription(
- si_signo, si_code, sigfault.si_addr, sigfault.bounds._addr_bnd._lower,
- sigfault.bounds._addr_bnd._upper);
+ si_signo, si_code, sifields.sigfault.si_addr,
+ sifields.sigfault.bounds._addr_bnd._lower,
+ sifie...
[truncated]
``````````
</details>
https://github.com/llvm/llvm-project/pull/140150
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