Zero-extending results of atomic probe operations fails with:
verifier bug. zext_dst is set, but no reg is defined
The problem is that insn_def_regno() handles BPF_ATOMICs, but not
BPF_PROBE_ATOMICs. Fix by adding the missing condition.
Fixes: d503a04f8bc0 ("bpf: Add support for certain atomics in bpf_arena to x86 JIT")
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index d3927d819465..e25ad5fb9115 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3217,7 +3217,8 @@ static int insn_def_regno(const struct bpf_insn *insn)
case BPF_ST:
return -1;
case BPF_STX:
- if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+ if ((BPF_MODE(insn->code) == BPF_ATOMIC ||
+ BPF_MODE(insn->code) == BPF_PROBE_ATOMIC) &&
(insn->imm & BPF_FETCH)) {
if (insn->imm == BPF_CMPXCHG)
return BPF_REG_0;
--
2.45.2
