Re: kern/60220 (kernel panic after modifying floating-point status register)

The following reply was made to PR kern/60220; it has been noted by GNATS.

From: Bruno Haible <[email protected]>
To: Taylor R Campbell <[email protected]>
Cc: [email protected], [email protected],
 [email protected], [email protected]
Subject:  Re: kern/60220 (kernel panic after modifying floating-point status register)
Date: Mon, 03 Aug 2026 00:30:58 +0200

 Taylor R Campbell wrote:
 > Still haven't reproduced it, but I don't have vbox handy to test.
 > Were you able to reproduce it in any environment other than vbox?
 
 Yes, I have so far reproduced it with
   - VirtualBox 7.0.x in an Ubuntu 24.04 host,
   - VirtualBox 7.2.x in an Ubuntu 26.04 host,
   - qemu 10.1.1 in an Ubuntu 26.04 host, with qemu option -enable-kvm.
 
 I do *not* reproduce it with
   - qemu 10.1.1 in an Ubuntu 26.04 host, without qemu option -enable-kvm.
 In this setting "make check" fails (unlike in NetBSD 10.0, where it succeeded),
 but it does not crash the kernel.
 
 > But the first line of ps-part1.png shows that the process running your
 > test program is still on the CPU:
 
 "make check" runs the same program few dozens of times.
 
 > Can you try running the NetBSD ATF tests in this environment to see if
 > they also reproduce the crash?
 > 
 > cd /usr/tests/lib/libc && atf-run | atf-report
 > cd /usr/tests/lib/libm && atf-run | atf-report
 > cd /usr/tests/kernel && atf-run | atf-report
 
 * In the VirtualBox 7.2.x environment:
   sigfpe_flt: Passed.
   No crash.
 
 * In the QEMU environment (both with and without -enable-kvm):
   sigfpe_flt: Skipped: Test does not run correctly under QEMU
   No crash.