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bpf: arm64: Silence "UBSAN: negation-overflow" warning

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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>
This commit is contained in:
Song Liu
2025-02-18 00:02:40 -08:00
committed by Alexei Starovoitov
parent 201b62ccc8
commit 239860828f
1 changed files with 3 additions and 3 deletions
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6
arch/arm64/net/bpf_jit_comp.c
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@@ -272,7 +272,7 @@ 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);
@@ -1159,7 +1159,7 @@ emit_bswap_uxt:
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);
@@ -1330,7 +1330,7 @@ emit_cond_jmp:
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);