[PATCH v3] bpf: Fix unsigned 'datasec_id' compared with zero in check_pseudo_btf_id

From: xiakaixu1987
Date: Wed Nov 11 2020 - 00:03:59 EST


From: Kaixu Xia <kaixuxia@xxxxxxxxxxx>

The unsigned variable datasec_id is assigned a return value from the call
to check_pseudo_btf_id(), which may return negative error code.

Fixes coccicheck warning:

./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0

Reported-by: Tosk Robot <tencent_os_robot@xxxxxxxxxxx>
Signed-off-by: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
---
v3:
-put the changes on the proper place.

v2:
-split out datasec_id definition into a separate line.

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 6200519582a6..6204ec705d80 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -9572,12 +9572,13 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
struct bpf_insn *insn,
struct bpf_insn_aux_data *aux)
{
- u32 datasec_id, type, id = insn->imm;
const struct btf_var_secinfo *vsi;
const struct btf_type *datasec;
const struct btf_type *t;
const char *sym_name;
bool percpu = false;
+ u32 type, id = insn->imm;
+ s32 datasec_id;
u64 addr;
int i;

--
2.20.0