[LLDB][MIPS] To handle SI_KERNEL generated for invalid 64 bit address

[nitesh.jain]

Summary

In case of MIPS64 target for invalid 64 bit address ,it generated SIGBUS signal with si_code=SI_KERNEL. This patch handle the above mentioned case.

[clayborg]

Is "SI_KERNEL" part of posix? I wonder if we need to put a "#ifdef SI_KERNEL" / "#endif" around this case and possibly other cases. If it is part of the POSIX spec, then this is good.

[nitesh.jain]

I think SI_KERNEL is not part of the POSIX specification. I will update the file with suggested changes.

Thanks

[clayborg]

So we are putting non-posix crash reasons into POSIX? Seems wrong to me. Seems like this should be detected in the linux specific code before letting a CrashReason.cpp crash reason if this is linux specific.

[nitesh.jain]

This patch handle checking for SI_KERNEL in NativeThreadLinux.cpp.

[clayborg]

Much better.

[clayborg]

Fix typo and good to go

source/Plugins/Process/Linux/NativeThreadLinux.cpp

267 ↗

(On Diff #30678)

type above: SI_KERENEL, should be SI_KERNEL

[ovyalov]

source/Plugins/Process/Linux/NativeThreadLinux.cpp

268 ↗

(On Diff #30678)

As an option to make more concise:

const auto reason = (info->si_signo == SIGBUS && info->si_code == SI_KERNEL) ? CrashReason::eInvalidAddress : GetCrashReason(*info);
m_stop_description = GetCrashReasonString(reason, reinterpret_cast<uintptr_t>(info->si_addr));

268 ↗

(On Diff #30678)

Please make sure that the change isn't introducing test regressions on Linux.

[nitesh.jain]

Fixed typo and modified file as per suggestion . This patch is tested on linux and working without any failures.

[clayborg]

Looks good.

[ovyalov]

LGTM

lldb/trunk/source/Plugins/Process/Linux/NativeThreadLinux.cpp

NativeThreadLinux::SetStoppedBySignal(uint32_t signo, const siginfo_t *info)
     const StateType new_state = StateType::eStateStopped;
     MaybeLogStateChange (new_state);
     m_state = new_state;
 
     m_stop_info.reason = StopReason::eStopReasonSignal;
     m_stop_info.details.signal.signo = signo;
 
     m_stop_description.clear();
+    if (info)
+    {
         switch (signo)
         {
         case SIGSEGV:
         case SIGBUS:
         case SIGFPE:
         case SIGILL:
-        if (! info)
-            break;
-        const auto reason = GetCrashReason(*info);
+             //In case of MIPS64 target, SI_KERNEL is generated for invalid 64bit address.
+             const auto reason = (info->si_signo == SIGBUS && info->si_code == SI_KERNEL) ? 
+                                  CrashReason::eInvalidAddress : GetCrashReason(*info);
              m_stop_description = GetCrashReasonString(reason, reinterpret_cast<uintptr_t>(info->si_addr));
              break;
         }
     }
+}
 
 bool
 NativeThreadLinux::IsStopped (int *signo)
 {
     if (!StateIsStoppedState (m_state, false))
         return false;
 
     // If we are stopped by a signal, return the signo.