# DF-2755 baseline run 1 — STOCK kernel (X86_64_GENERIC #0, INVARIANTS)
# unprivileged user maxx (uid 1001), guest 6x CPU (QEMU/KVM, -smp 6)
$ cc -O2 -pthread -o df2755 df2755.c          # BUILD_RC=0 (warnings only)
$ ./df2755 3 60
[*] leader pid 967 master=3 slave=4 (/dev/pts/0)
[*] 3 racer threads per side, 60s
    << ssh session never returned: guest PANICKED mid-run (serial console): >>

login: (interleaved) Secondary PANIC on CPU 5: THREAD 0xfffff8008e10...
panic: vref: bad refcnt 00000000 1
cpuid = 2
Trace beginning at frame 0xfffff801179107a8
vref() at vref+0x36 0xffffffff806f6bc6
vref() at vref+0x36 0xffffffff806f6bc6
devfs_fo_ioctl() at devfs_fo_ioctl+0x13f 0xffffffff80921c5f
mapped_ioctl() at mapped_ioctl+0x5fa 0xffffffff806a831a
syscall2() at syscall2+0x11e 0xffffffff80bd6a0e
Debugger("panic")
CPU2 stopping CPUs: 0x0000003b
 stopped
Stopped at Debugger+0x7c: movb $0,0xbdaf09(%rip)
db>