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path: root/arch/x86/net/bpf_jit_comp.c
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Diffstat (limited to 'arch/x86/net/bpf_jit_comp.c')
-rw-r--r--arch/x86/net/bpf_jit_comp.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index b725154182cc..263c8453815e 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -1027,7 +1027,17 @@ emit_cond_jmp: /* convert BPF opcode to x86 */
break;
case BPF_JMP | BPF_JA:
- jmp_offset = addrs[i + insn->off] - addrs[i];
+ if (insn->off == -1)
+ /* -1 jmp instructions will always jump
+ * backwards two bytes. Explicitly handling
+ * this case avoids wasting too many passes
+ * when there are long sequences of replaced
+ * dead code.
+ */
+ jmp_offset = -2;
+ else
+ jmp_offset = addrs[i + insn->off] - addrs[i];
+
if (!jmp_offset)
/* optimize out nop jumps */
break;
@@ -1226,6 +1236,7 @@ skip_init_addrs:
for (pass = 0; pass < 20 || image; pass++) {
proglen = do_jit(prog, addrs, image, oldproglen, &ctx);
if (proglen <= 0) {
+out_image:
image = NULL;
if (header)
bpf_jit_binary_free(header);
@@ -1236,8 +1247,7 @@ skip_init_addrs:
if (proglen != oldproglen) {
pr_err("bpf_jit: proglen=%d != oldproglen=%d\n",
proglen, oldproglen);
- prog = orig_prog;
- goto out_addrs;
+ goto out_image;
}
break;
}
@@ -1273,7 +1283,7 @@ skip_init_addrs:
prog = orig_prog;
}
- if (!prog->is_func || extra_pass) {
+ if (!image || !prog->is_func || extra_pass) {
out_addrs:
kfree(addrs);
kfree(jit_data);