From: Ravi Bangoria ravi.bangoria@linux.ibm.com
[ Upstream commit 328aac5ecd119ede3633f7d17969b1ff34ccc784 ]
Commit 4c5de127598e1 ("bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.") is emitting a couple of instructions before the actual load. Consider those additional instructions while calculating extable offset.
Fixes: 4c5de127598e1 ("bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.") Signed-off-by: Ravi Bangoria ravi.bangoria@linux.ibm.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/20210622110026.1157847-1-ravi.bangoria@linux.ibm... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/net/bpf_jit_comp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 2a2e290fa5d8..a3d867f22153 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1297,7 +1297,7 @@ st: if (is_imm8(insn->off)) emit_ldx(&prog, BPF_SIZE(insn->code), dst_reg, src_reg, insn->off); if (BPF_MODE(insn->code) == BPF_PROBE_MEM) { struct exception_table_entry *ex; - u8 *_insn = image + proglen; + u8 *_insn = image + proglen + (start_of_ldx - temp); s64 delta;
/* populate jmp_offset for JMP above */