Use SI_KERNEL on platforms defining it

[krytarowski]

Summary

Linux and FreeBSD occasionally send SI_KERNEL codes, nonexistent on other platforms.

Problem caught on NetBSD.

[krytarowski]

Still valid.

[sas]

Makes sense. Adding a tiny comment explaining which platforms get SI_KERNEL might be a good idea here.

[krytarowski]

In D12659#243415, @sas wrote:

Makes sense. Adding a tiny comment explaining which platforms get SI_KERNEL might be a good idea here.

Can I replace the following comment:

// Linux will occasionally send spurious SI_KERNEL codes.
// (this is poorly documented in sigaction)
// One way to get this is via unaligned SIMD loads.

To something more generic:

// Some platforms will occasionally send nonstandard spurious SI_KERNEL codes.
// One way to get this is via unaligned SIMD loads.

This is not exactly what you asked for but makes it more generic and thus not desynchronized with the reality when the time will pass.

[emaste]

In D12659#243729, @krytarowski wrote:

In D12659#243415, @sas wrote:

To something more generic:

// Some platforms will occasionally send nonstandard spurious SI_KERNEL codes.
// One way to get this is via unaligned SIMD loads.

This is not exactly what you asked for but makes it more generic and thus not desynchronized with the reality when the time will pass.

I agree - there's no point in trying to manually keep a list in the comment up to date.

[krytarowski]

Rework the comment regarding SI_KERNEL.

[krytarowski]

Please commit it if it's OK.

[sas]

Committed as r247579.

source/Plugins/Process/POSIX/CrashReason.cpp

 
 CrashReason
 GetCrashReasonForSIGSEGV(const siginfo_t& info)
 {
     assert(info.si_signo == SIGSEGV);
 
     switch (info.si_code)
     {
+#ifdef SI_KERNEL
     case SI_KERNEL:
         // Linux will occasionally send spurious SI_KERNEL codes.
         // (this is poorly documented in sigaction)
         // One way to get this is via unaligned SIMD loads.
         return CrashReason::eInvalidAddress; // for lack of anything better
+#endif
     case SEGV_MAPERR:
         return CrashReason::eInvalidAddress;
     case SEGV_ACCERR:
         return CrashReason::ePrivilegedAddress;
     }
 
     assert(false && "unexpected si_code for SIGSEGV");
     return CrashReason::eInvalidCrashReason;