6.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Song Liu song@kernel.org
[ Upstream commit 239860828f8660e2be487e2fbdae2640cce3fd67 ]
With UBSAN, test_bpf.ko triggers warnings like:
UBSAN: negation-overflow in arch/arm64/net/bpf_jit_comp.c:1333:28 negation of -2147483648 cannot be represented in type 's32' (aka 'int'):
Silence these warnings by casting imm to u32 first.
Reported-by: Breno Leitao leitao@debian.org Signed-off-by: Song Liu song@kernel.org Tested-by: Breno Leitao leitao@debian.org Link: https://lore.kernel.org/r/20250218080240.2431257-1-song@kernel.org Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/net/bpf_jit_comp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 3126881fe6768..970c49bb7ed47 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -274,7 +274,7 @@ static inline void emit_a64_add_i(const bool is64, const int dst, const int src, { if (is_addsub_imm(imm)) { emit(A64_ADD_I(is64, dst, src, imm), ctx); - } else if (is_addsub_imm(-imm)) { + } else if (is_addsub_imm(-(u32)imm)) { emit(A64_SUB_I(is64, dst, src, -imm), ctx); } else { emit_a64_mov_i(is64, tmp, imm, ctx); @@ -1208,7 +1208,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, case BPF_ALU64 | BPF_SUB | BPF_K: if (is_addsub_imm(imm)) { emit(A64_SUB_I(is64, dst, dst, imm), ctx); - } else if (is_addsub_imm(-imm)) { + } else if (is_addsub_imm(-(u32)imm)) { emit(A64_ADD_I(is64, dst, dst, -imm), ctx); } else { emit_a64_mov_i(is64, tmp, imm, ctx); @@ -1379,7 +1379,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, case BPF_JMP32 | BPF_JSLE | BPF_K: if (is_addsub_imm(imm)) { emit(A64_CMP_I(is64, dst, imm), ctx); - } else if (is_addsub_imm(-imm)) { + } else if (is_addsub_imm(-(u32)imm)) { emit(A64_CMN_I(is64, dst, -imm), ctx); } else { emit_a64_mov_i(is64, tmp, imm, ctx);