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-rw-r--r--arch/x86/net/bpf_jit_comp.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index b725154182cc..abce27ceb411 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;