[PATCH v3] libbpf: Improve debug message when the base BTF cannot be found

[PATCH v3] libbpf: Improve debug message when the base BTF cannot be found

[Ben Olson]

When running `bpftool` on a kernel module installed in `/lib/modules...`,
this error is encountered if the user does not specify `--base-btf` to
point to a valid base BTF (e.g. usually in `/sys/kernel/btf/vmlinux`).
However, looking at the debug output to determine the cause of the error
simply says `Invalid BTF string section`, which does not point to the
actual source of the error. This just improves that debug message to tell
users what happened.

Signed-off-by: Ben Olson <matthew.olson@intel.com>
---
 tools/lib/bpf/btf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 12468ae0d573..a4ae2df68b91 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -283,7 +283,7 @@ static int btf_parse_str_sec(struct btf *btf)
 		return -EINVAL;
 	}
 	if (!btf->base_btf && start[0]) {
-		pr_debug("Invalid BTF string section\n");
+		pr_debug("Malformed BTF string section, did you forget to provide base BTF?\n");
 		return -EINVAL;
 	}
 	return 0;
-- 
2.47.0

Re: [PATCH v3] libbpf: Improve debug message when the base BTF cannot be found

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Tue, 26 Nov 2024 14:08:45 -0600 you wrote:
> When running `bpftool` on a kernel module installed in `/lib/modules...`,
> this error is encountered if the user does not specify `--base-btf` to
> point to a valid base BTF (e.g. usually in `/sys/kernel/btf/vmlinux`).
> However, looking at the debug output to determine the cause of the error
> simply says `Invalid BTF string section`, which does not point to the
> actual source of the error. This just improves that debug message to tell
> users what happened.
> 
> [...]

Here is the summary with links:
  - [v3] libbpf: Improve debug message when the base BTF cannot be found
    https://git.kernel.org/bpf/bpf-next/c/c8d02b547363

You are awesome, thank you!
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