RFR: 8359820: SIGILL with low -XX:HandshakeTimeout

[David Holmes]

On Tue, 15 Jul 2025 08:37:38 GMT, Anton Artemov <duke at openjdk.org> wrote:

> Hi, please consider the following changes:
> 
> we augment the SIGILL handling in `os::signal_thread` with proper logging so that the initial crash information goes to stdout/stderr as well. 
> 
> The problem in the issue description is not a problem by itself, the behavior is not unexpected, but it is somewhat difficult to find out what caused SIGILL to be fired.
> 
> Tested in tiers 1-3.

@toxaart I'm really looking for something in the fatal error handler so that instead of seeing just:

#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGILL (0x4) at pc=0x00007d9dc5a98d71 (sent by kill), pid=329828, tid=329852
#
# JRE version: Java(TM) SE Runtime Environment (26.0+3) (fastdebug build 26-ea+3-153)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 26-ea+3-153, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
# Problematic frame:
# C [libc.so.6+0x98d71] 


There is something there that indicates it was a handshake timeout. E.g.


# SIGILL (0x4) at pc=0x00007d9dc5a98d71 (sent by handshake timeout handlerl), pid=329828, tid=329852


We may need the handshake code to set a flag on the target Thread that the error code can query if it sees a SIGILL.

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PR Comment: https://git.openjdk.org/jdk/pull/26309#issuecomment-3076476604