--- variant A2: mmap_alias_rw (baseline: pmap_kextract fatal trap 12 during mmap) ---
[*] DF-3879 variant A2: wrapped-offset kernel-alias proof (prepared channel)
    off      = 0xffffffff00000000
    size     = 0x100000000
    sum      = 0x0000000000000000 (wraps mod 2^64; <= bufsize -> dsp.c:2342 PASSES)
    ofs      = (u32)off = 0x0  ->  wild = b->buf + 0
[+] open("/dev/dsp", O_RDWR) ok (0666 cdev)
[+] OSS setup ok: fragsize=2048 fragments=32 bytes=65536 (bufsoft allocated)
[-] wild mmap: Invalid argument (errno=22) — check NOT bypassed?
exit=3
guest: up

--- sanity: legit mmap(off=0, size=bufsize) must still work ---
[*] bufsize=65536
[+] legit mmap ok, RW works ("LEGIT-OK") — feature preserved
exit=0
guest: up