On Wed, Oct 23, 2024 at 8:53 AM Mykyta Yatsenko
<mykyta.yatsenko5@xxxxxxxxx> wrote:
>
> From: Mykyta Yatsenko <yatsenko@xxxxxxxx>
>
> The current default buffer size of 16MB allocated by veristat is no
> longer sufficient to hold the verifier logs of some production BPF
> programs. To address this issue, we need to increase the verifier log
> limit.
> Commit 7a9f5c65abcc ("bpf: increase verifier log limit") has already
> increased the supported buffer size by the kernel, but veristat users
> need to explicitly pass a log size argument to use the bigger log.
>
> This patch adds a function to detect the maximum verifier log size
> supported by the kernel and uses that by default in veristat.
> This ensures that veristat can handle larger verifier logs without
> requiring users to manually specify the log size.
>
> Signed-off-by: Mykyta Yatsenko <yatsenko@xxxxxxxx>
> ---
> tools/testing/selftests/bpf/veristat.c | 42 +++++++++++++++++++++++++-
> 1 file changed, 41 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/veristat.c b/tools/testing/selftests/bpf/veristat.c
> index c8efd44590d9..a8498b1a2898 100644
> --- a/tools/testing/selftests/bpf/veristat.c
> +++ b/tools/testing/selftests/bpf/veristat.c
> @@ -16,6 +16,7 @@
> #include <sys/stat.h>
> #include <bpf/libbpf.h>
> #include <bpf/btf.h>
> +#include <bpf/bpf.h>
> #include <libelf.h>
> #include <gelf.h>
> #include <float.h>
> @@ -1109,6 +1110,45 @@ static void fixup_obj(struct bpf_object *obj, struct bpf_program *prog, const ch
> return;
> }
>
> +static int max_verifier_log_size(void)
> +{
> + const int SMALL_LOG_SIZE = UINT_MAX >> 8;
> + const int BIG_LOG_SIZE = UINT_MAX >> 2;
> + struct bpf_insn insns[] = {
> + {
> + .code = BPF_ALU | BPF_MOV | BPF_X,
> + .dst_reg = BPF_REG_0,
> + .src_reg = 0,
> + .off = 0,
> + .imm = 0 },
> + {
> + .code = BPF_JMP | BPF_EXIT,
> + .dst_reg = 0,
> + .src_reg = 0,
> + .off = 0,
> + .imm = 0 },
> + };
I reformated this:
diff --git a/tools/testing/selftests/bpf/veristat.c
b/tools/testing/selftests/bpf/veristat.c
index a8498b1a2898..e12ef953fba8 100644
--- a/tools/testing/selftests/bpf/veristat.c
+++ b/tools/testing/selftests/bpf/veristat.c
@@ -1115,18 +1115,8 @@ static int max_verifier_log_size(void)
const int SMALL_LOG_SIZE = UINT_MAX >> 8;
const int BIG_LOG_SIZE = UINT_MAX >> 2;
struct bpf_insn insns[] = {
- {
- .code = BPF_ALU | BPF_MOV | BPF_X,
- .dst_reg = BPF_REG_0,
- .src_reg = 0,
- .off = 0,
- .imm = 0 },
- {
- .code = BPF_JMP | BPF_EXIT,
- .dst_reg = 0,
- .src_reg = 0,
- .off = 0,
- .imm = 0 },
+ { .code = BPF_ALU | BPF_MOV | BPF_X, .dst_reg = BPF_REG_0, },
+ { .code = BPF_JMP | BPF_EXIT, },
};
LIBBPF_OPTS(bpf_prog_load_opts, opts,
.log_size = BIG_LOG_SIZE,
Applied to bpf-next, thanks!
> + LIBBPF_OPTS(bpf_prog_load_opts, opts,
> + .log_size = BIG_LOG_SIZE,
> + .log_buf = (void *)-1,
> + .log_level = 4
> + );
> + int ret, insn_cnt = ARRAY_SIZE(insns);
> + static int log_size;
> +
> + if (log_size != 0)
> + return log_size;
> +
> + ret = bpf_prog_load(BPF_PROG_TYPE_TRACEPOINT, NULL, "GPL", insns, insn_cnt, &opts);
> +
> + if (ret == -EFAULT)
> + log_size = BIG_LOG_SIZE;
> + else /* ret == -EINVAL, big log size is not supported by the verifier */
> + log_size = SMALL_LOG_SIZE;
> +
> + return log_size;
> +}
> +
> static int process_prog(const char *filename, struct bpf_object *obj, struct bpf_program *prog)
> {
> const char *base_filename = basename(strdupa(filename));
> @@ -1132,7 +1172,7 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
> memset(stats, 0, sizeof(*stats));
>
> if (env.verbose || env.top_src_lines > 0) {
> - buf_sz = env.log_size ? env.log_size : 16 * 1024 * 1024;
> + buf_sz = env.log_size ? env.log_size : max_verifier_log_size();
> buf = malloc(buf_sz);
> if (!buf)
> return -ENOMEM;
> --
> 2.47.0
>
