On Fri, Mar 01, 2024 at 12:41:06PM +0000, Alan Maguire wrote:
> Use consistent method across allocating function and per-cpu variable
> representations, based around (re)allocating the arrays based on demand.
> This avoids issues where the number of per-CPU variables exceeds the
> hardcoded limit.
>
> Reported-by: John Hubbard <jhubbard@xxxxxxxxxx>
> Suggested-by: Jiri Olsa <olsajiri@xxxxxxxxx>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> Tested-by: John Hubbard <jhubbard@xxxxxxxxxx>
Acked/Tested-by: Jiri Olsa <jolsa@xxxxxxxxxx>
thanks,
jirka
> ---
> btf_encoder.c | 38 +++++++++++++++++++++++++++++---------
> 1 file changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/btf_encoder.c b/btf_encoder.c
> index fd04008..a43d702 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -50,8 +50,6 @@ struct elf_function {
> struct btf_encoder_state state;
> };
>
> -#define MAX_PERCPU_VAR_CNT 4096
> -
> struct var_info {
> uint64_t addr;
> const char *name;
> @@ -80,8 +78,9 @@ struct btf_encoder {
> is_rel;
> uint32_t array_index_id;
> struct {
> - struct var_info vars[MAX_PERCPU_VAR_CNT];
> + struct var_info *vars;
> int var_cnt;
> + int allocated;
> uint32_t shndx;
> uint64_t base_addr;
> uint64_t sec_sz;
> @@ -983,6 +982,16 @@ static int functions_cmp(const void *_a, const void *_b)
> #define max(x, y) ((x) < (y) ? (y) : (x))
> #endif
>
> +static void *reallocarray_grow(void *ptr, int *nmemb, size_t size)
> +{
> + int new_nmemb = max(1000, *nmemb * 3 / 2);
> + void *new = realloc(ptr, new_nmemb * size);
> +
> + if (new)
> + *nmemb = new_nmemb;
> + return new;
> +}
> +
> static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *sym)
> {
> struct elf_function *new;
> @@ -995,8 +1004,9 @@ static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *
> return 0;
>
> if (encoder->functions.cnt == encoder->functions.allocated) {
> - encoder->functions.allocated = max(1000, encoder->functions.allocated * 3 / 2);
> - new = realloc(encoder->functions.entries, encoder->functions.allocated * sizeof(*encoder->functions.entries));
> + new = reallocarray_grow(encoder->functions.entries,
> + &encoder->functions.allocated,
> + sizeof(*encoder->functions.entries));
> if (!new) {
> /*
> * The cleanup - delete_functions is called
> @@ -1439,10 +1449,17 @@ static int btf_encoder__collect_percpu_var(struct btf_encoder *encoder, GElf_Sym
> if (!encoder->is_rel)
> addr -= encoder->percpu.base_addr;
>
> - if (encoder->percpu.var_cnt == MAX_PERCPU_VAR_CNT) {
> - fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
> - MAX_PERCPU_VAR_CNT);
> - return -1;
> + if (encoder->percpu.var_cnt == encoder->percpu.allocated) {
> + struct var_info *new;
> +
> + new = reallocarray_grow(encoder->percpu.vars,
> + &encoder->percpu.allocated,
> + sizeof(*encoder->percpu.vars));
> + if (!new) {
> + fprintf(stderr, "Failed to allocate memory for variables\n");
> + return -1;
> + }
> + encoder->percpu.vars = new;
> }
> encoder->percpu.vars[encoder->percpu.var_cnt].addr = addr;
> encoder->percpu.vars[encoder->percpu.var_cnt].sz = size;
> @@ -1720,6 +1737,9 @@ void btf_encoder__delete(struct btf_encoder *encoder)
> encoder->functions.allocated = encoder->functions.cnt = 0;
> free(encoder->functions.entries);
> encoder->functions.entries = NULL;
> + encoder->percpu.allocated = encoder->percpu.var_cnt = 0;
> + free(encoder->percpu.vars);
> + encoder->percpu.vars = NULL;
>
> free(encoder);
> }
> --
> 2.39.3
>
