6.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
[ Upstream commit df34ec9db6f521118895f22795da49f2ec01f8cf ]
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>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240701234304.14336-2-iii@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 214a9fa8c6fb7..e1e08e62a2f2f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3215,7 +3215,8 @@ 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;
--
2.43.0
