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bpf, x86: Fix extable offset calculation

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Commit 4c5de12759 ("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: 4c5de12759 ("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.com
This commit is contained in:
Ravi Bangoria 2021-06-22 16:30:26 +05:30 committed by Daniel Borkmann
parent a196fa78a2
commit 328aac5ecd
1 changed files with 1 additions and 1 deletions
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arch/x86/net/bpf_jit_comp.c
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@ -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 */