Comment # 24 on bug 1111657 from Andreas Schwab

That must be a kernel bug.  The same insn at the same address with the same
operands produces different results on two calls.

(gdb) 
0xf7b1f2ef      143       cor = (ssn + s * ccs - sn * c) + cs * s;
1: x/i $pc
=> 0xf7b1f2ef <__cos+831>:      fldl   -0x1e2f8(%ebx,%eax,8)
2: $st0 = 1.43323328782651048725e-20
(gdb) 
0xf7b1f2f6      143       cor = (ssn + s * ccs - sn * c) + cs * s;
1: x/i $pc
=> 0xf7b1f2f6 <__cos+838>:      faddp  %st,%st(1)
2: $st0 = -nan(0xc000000000000000)
(gdb) x/x $ebx + $eax * 8 -0x1e2f8
0xf7b9c288:     0xac3fe0cb
(gdb) 
0xf7b9c28c:     0x3c67c74b


(gdb) 
0xf7b1f2ef      143       cor = (ssn + s * ccs - sn * c) + cs * s;
1: x/i $pc
=> 0xf7b1f2ef <__cos+831>:      fldl   -0x1e2f8(%ebx,%eax,8)
2: $st0 = 1.43323328782651048725e-20
(gdb) 
0xf7b1f2f6      143       cor = (ssn + s * ccs - sn * c) + cs * s;
1: x/i $pc
=> 0xf7b1f2f6 <__cos+838>:      faddp  %st,%st(1)
2: $st0 = 1.03122798607872161491e-17
(gdb) x/x $ebx + $eax * 8 -0x1e2f8
0xf7b9c288:     0xac3fe0cb
(gdb) 
0xf7b9c28c:     0x3c67c74b