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test_bpf: add more eBPF jump torture cases 

Add two more eBPF test cases for JITs, i.e. the second one revealed a
bug in the x86_64 JIT compiler, where only an int3 filled image from
the allocator was emitted and later wrongly set by the compiler as the
bpf_func program code since optimization pass boundary was surpassed
w/o actually emitting opcodes.

Interpreter:

  [   45.782892] test_bpf: #242 BPF_MAXINSNS: Very long jump backwards jited:0 11 PASS
  [   45.783062] test_bpf: #243 BPF_MAXINSNS: Edge hopping nuthouse jited:0 14705 PASS

After x86_64 JIT (fixed):

  [   80.495638] test_bpf: #242 BPF_MAXINSNS: Very long jump backwards jited:1 6 PASS
  [   80.495957] test_bpf: #243 BPF_MAXINSNS: Edge hopping nuthouse jited:1 17157 PASS

Reference: http://thread.gmane.org/gmane.linux.network/364729
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
steinar/wifi_calib_4_9_kernel
Daniel Borkmann 2015-05-23 01:10:07 +02:00 committed by David S. Miller
parent cff497c870
commit 3b52960266
1 changed files with 67 additions and 0 deletions
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67
lib/test_bpf.c
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@ -263,6 +263,57 @@ static int bpf_fill_maxinsns8(struct bpf_test *self)
return 0;
}
static int bpf_fill_maxinsns9(struct bpf_test *self)
{
unsigned int len = BPF_MAXINSNS;
struct bpf_insn *insn;
int i;
insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);
if (!insn)
return -ENOMEM;
insn[0] = BPF_JMP_IMM(BPF_JA, 0, 0, len - 2);
insn[1] = BPF_ALU32_IMM(BPF_MOV, R0, 0xcbababab);
insn[2] = BPF_EXIT_INSN();
for (i = 3; i < len - 2; i++)
insn[i] = BPF_ALU32_IMM(BPF_MOV, R0, 0xfefefefe);
insn[len - 2] = BPF_EXIT_INSN();
insn[len - 1] = BPF_JMP_IMM(BPF_JA, 0, 0, -(len - 1));
self->u.ptr.insns = insn;
self->u.ptr.len = len;
return 0;
}
static int bpf_fill_maxinsns10(struct bpf_test *self)
{
unsigned int len = BPF_MAXINSNS, hlen = len - 2;
struct bpf_insn *insn;
int i;
insn = kmalloc_array(len, sizeof(*insn), GFP_KERNEL);
if (!insn)
return -ENOMEM;
for (i = 0; i < hlen / 2; i++)
insn[i] = BPF_JMP_IMM(BPF_JA, 0, 0, hlen - 2 - 2 * i);
for (i = hlen - 1; i > hlen / 2; i--)
insn[i] = BPF_JMP_IMM(BPF_JA, 0, 0, hlen - 1 - 2 * i);
insn[hlen / 2] = BPF_JMP_IMM(BPF_JA, 0, 0, hlen / 2 - 1);
insn[hlen] = BPF_ALU32_IMM(BPF_MOV, R0, 0xabababac);
insn[hlen + 1] = BPF_EXIT_INSN();
self->u.ptr.insns = insn;
self->u.ptr.len = len;
return 0;
}
static struct bpf_test tests[] = {
{
"TAX",
@ -4268,6 +4319,22 @@ static struct bpf_test tests[] = {
{ { 0, 0xffffffff } },
.fill_helper = bpf_fill_maxinsns8,
},
{ /* Mainly checking JIT here. */
"BPF_MAXINSNS: Very long jump backwards",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 0xcbababab } },
.fill_helper = bpf_fill_maxinsns9,
},
{ /* Mainly checking JIT here. */
"BPF_MAXINSNS: Edge hopping nuthouse",
{ },
INTERNAL | FLAG_NO_DATA,
{ },
{ { 0, 0xabababac } },
.fill_helper = bpf_fill_maxinsns10,
},
};
static struct net_device dev;