Full error report:

vex amd64->IR: unhandled instruction bytes: 0x62 0xF1 0x7F 0x28 0x7F 0x84 0x24 0xA8 0xFF 0xFF
vex amd64->IR:   REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0
vex amd64->IR:   VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE
vex amd64->IR:   PFX.66=0 PFX.F2=0 PFX.F3=0
==577== valgrind: Unrecognised instruction at address 0x40195bd.
==577==    at 0x40195BD: _dl_sysdep_parse_arguments (dl-sysdep.c:90)
==577==    by 0x401A146: _dl_sysdep_start (dl-sysdep.c:106)
==577==    by 0x401BB3C: _dl_start_final (rtld.c:497)
==577==    by 0x401BB3C: _dl_start (rtld.c:584)
==577==    by 0x401A9D7: ??? (in /lib64/ld-linux-x86-64.so.2)

This is pretty major, as this instruction is encountered in dynamic linker ld-linux-x86-64.so.2, which renders Valgrind basically unusable on my machine (and, I suspect, on any other modern source-based distro).