Commit 328aac5e authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Daniel Borkmann
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bpf, x86: Fix extable offset calculation 



Commit 4c5de127 ("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: 4c5de127 ("bpf: Emit explicit NULL pointer checks for PROBE_LDX instructions.")
Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210622110026.1157847-1-ravi.bangoria@linux.ibm.com
parent a196fa78

arch/x86/net/bpf_jit_comp.c

+1 −1
Original line number Diff line number Diff line
@@ -1281,7 +1281,7 @@ 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 */