diff mbox series

[bpf-next,v4,1/2] bpf: clean-up bpf_verifier_vlog() for BPF_LOG_KERNEL log level

Message ID 20211201073458.2731595-2-houtao1@huawei.com (mailing list archive)
State Accepted
Delegated to: BPF
Headers show
Series clean-up for BPF_LOG_KERNEL log level | expand

Checks

Context Check Description
bpf/vmtest-bpf-next success VM_Test
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/cc_maintainers warning 3 maintainers not CCed: kpsingh@kernel.org songliubraving@fb.com john.fastabend@gmail.com
netdev/build_clang success Errors and warnings before: 22 this patch: 22
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 20 this patch: 20
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 19 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Hou Tao Dec. 1, 2021, 7:34 a.m. UTC 
An extra newline will output for bpf_log() with BPF_LOG_KERNEL level
as shown below:

[   52.095704] BPF:The function test_3 has 12 arguments. Too many.
[   52.095704]
[   52.096896] Error in parsing func ptr test_3 in struct bpf_dummy_ops

Now all bpf_log() are ended by newline, but not all btf_verifier_log()
are ended by newline, so checking whether or not the log message
has the trailing newline and adding a newline if not.

Also there is no need to calculate the left userspace buffer size
for kernel log output and to truncate the output by '\0' which
has already been done by vscnprintf(), so only do these for
userspace log output.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 kernel/bpf/verifier.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

Alexei Starovoitov Dec. 1, 2021, 5:50 p.m. UTC | #1 
On Tue, Nov 30, 2021 at 11:19 PM Hou Tao <houtao1@huawei.com> wrote:
>
> An extra newline will output for bpf_log() with BPF_LOG_KERNEL level
> as shown below:
>
> [   52.095704] BPF:The function test_3 has 12 arguments. Too many.
> [   52.095704]
> [   52.096896] Error in parsing func ptr test_3 in struct bpf_dummy_ops
>
> Now all bpf_log() are ended by newline, but not all btf_verifier_log()
> are ended by newline, so checking whether or not the log message
> has the trailing newline and adding a newline if not.
>
> Also there is no need to calculate the left userspace buffer size
> for kernel log output and to truncate the output by '\0' which
> has already been done by vscnprintf(), so only do these for
> userspace log output.
>
> Signed-off-by: Hou Tao <houtao1@huawei.com>
> Acked-by: Yonghong Song <yhs@fb.com>
> Acked-by: Martin KaFai Lau <kafai@fb.com>

Applied this patch. Thanks
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 6cfd628ae3e4..722aea00d44e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -293,13 +293,15 @@  void bpf_verifier_vlog(struct bpf_verifier_log *log, const char *fmt,
 	WARN_ONCE(n >= BPF_VERIFIER_TMP_LOG_SIZE - 1,
 		  "verifier log line truncated - local buffer too short\n");
 
-	n = min(log->len_total - log->len_used - 1, n);
-	log->kbuf[n] = '\0';
-
 	if (log->level == BPF_LOG_KERNEL) {
-		pr_err("BPF:%s\n", log->kbuf);
+		bool newline = n > 0 && log->kbuf[n - 1] == '\n';
+
+		pr_err("BPF: %s%s", log->kbuf, newline ? "" : "\n");
 		return;
 	}
+
+	n = min(log->len_total - log->len_used - 1, n);
+	log->kbuf[n] = '\0';
 	if (!copy_to_user(log->ubuf + log->len_used, log->kbuf, n + 1))
 		log->len_used += n;
 	else