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authorMartin KaFai Lau <martin.lau@kernel.org>2024-08-29 23:08:23 +0200
committerAlexei Starovoitov <ast@kernel.org>2024-08-30 03:15:44 +0200
commit6f606ffd6dd7583d8194ee3d858ba4da2eff26a3 (patch)
tree15ee846fad685ad7723b7889332bf003973c2b37
parentbpf: Use kvmemdup to simplify the code (diff)
downloadlinux-6f606ffd6dd7583d8194ee3d858ba4da2eff26a3.tar.xz
linux-6f606ffd6dd7583d8194ee3d858ba4da2eff26a3.zip
bpf: Move insn_buf[16] to bpf_verifier_env
This patch moves the 'struct bpf_insn insn_buf[16]' stack usage to the bpf_verifier_env. A '#define INSN_BUF_SIZE 16' is also added to replace the ARRAY_SIZE(insn_buf) usages. Both convert_ctx_accesses() and do_misc_fixup() are changed to use the env->insn_buf. It is a refactoring work for adding the epilogue_buf[16] in a later patch. With this patch, the stack size usage decreased. Before: ./kernel/bpf/verifier.c:22133:5: warning: stack frame size (2584) After: ./kernel/bpf/verifier.c:22184:5: warning: stack frame size (2264) Reviewed-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://lore.kernel.org/r/20240829210833.388152-2-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--include/linux/bpf_verifier.h3
-rw-r--r--kernel/bpf/verifier.c15
2 files changed, 11 insertions, 7 deletions
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 279b4a640644..0ad2d189c546 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -23,6 +23,8 @@
* (in the "-8,-16,...,-512" form)
*/
#define TMP_STR_BUF_LEN 320
+/* Patch buffer size */
+#define INSN_BUF_SIZE 16
/* Liveness marks, used for registers and spilled-regs (in stack slots).
* Read marks propagate upwards until they find a write mark; they record that
@@ -780,6 +782,7 @@ struct bpf_verifier_env {
* e.g., in reg_type_str() to generate reg_type string
*/
char tmp_str_buf[TMP_STR_BUF_LEN];
+ struct bpf_insn insn_buf[INSN_BUF_SIZE];
};
static inline struct bpf_func_info_aux *subprog_aux(struct bpf_verifier_env *env, int subprog)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f32e3b9bb4e5..261849384ea8 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -19677,7 +19677,8 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
const struct bpf_verifier_ops *ops = env->ops;
int i, cnt, size, ctx_field_size, delta = 0;
const int insn_cnt = env->prog->len;
- struct bpf_insn insn_buf[16], *insn;
+ struct bpf_insn *insn_buf = env->insn_buf;
+ struct bpf_insn *insn;
u32 target_size, size_default, off;
struct bpf_prog *new_prog;
enum bpf_access_type type;
@@ -19690,7 +19691,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
}
cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
env->prog);
- if (cnt >= ARRAY_SIZE(insn_buf)) {
+ if (cnt >= INSN_BUF_SIZE) {
verbose(env, "bpf verifier is misconfigured\n");
return -EINVAL;
} else if (cnt) {
@@ -19837,7 +19838,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
target_size = 0;
cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
&target_size);
- if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
+ if (cnt == 0 || cnt >= INSN_BUF_SIZE ||
(ctx_field_size && !target_size)) {
verbose(env, "bpf verifier is misconfigured\n");
return -EINVAL;
@@ -19846,7 +19847,7 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
if (is_narrower_load && size < target_size) {
u8 shift = bpf_ctx_narrow_access_offset(
off, size, size_default) * 8;
- if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
+ if (shift && cnt + 1 >= INSN_BUF_SIZE) {
verbose(env, "bpf verifier narrow ctx load misconfigured\n");
return -EINVAL;
}
@@ -20391,7 +20392,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
const int insn_cnt = prog->len;
const struct bpf_map_ops *ops;
struct bpf_insn_aux_data *aux;
- struct bpf_insn insn_buf[16];
+ struct bpf_insn *insn_buf = env->insn_buf;
struct bpf_prog *new_prog;
struct bpf_map *map_ptr;
int i, ret, cnt, delta = 0, cur_subprog = 0;
@@ -20510,7 +20511,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
(BPF_MODE(insn->code) == BPF_ABS ||
BPF_MODE(insn->code) == BPF_IND)) {
cnt = env->ops->gen_ld_abs(insn, insn_buf);
- if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+ if (cnt == 0 || cnt >= INSN_BUF_SIZE) {
verbose(env, "bpf verifier is misconfigured\n");
return -EINVAL;
}
@@ -20803,7 +20804,7 @@ static int do_misc_fixups(struct bpf_verifier_env *env)
cnt = ops->map_gen_lookup(map_ptr, insn_buf);
if (cnt == -EOPNOTSUPP)
goto patch_map_ops_generic;
- if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+ if (cnt <= 0 || cnt >= INSN_BUF_SIZE) {
verbose(env, "bpf verifier is misconfigured\n");
return -EINVAL;
}