bpf: extend bpf_trace_printk to support %i (7bda4b40) · Commits · 戴 / test

Currently, bpf_trace_printk does not support common formatting symbol '%i' however vsprintf does and is what eventually gets called by bpf helper. If users are used to '%i' and currently make use of it, then bpf_trace_printk will just return with error without dumping anything to the trace pipe, so just add support for '%i' to the helper. Signed-off-by:

John Fastabend <john.fastabend@gmail.com> Acked-by:

Daniel Borkmann <daniel@iogearbox.net> Acked-by:

Alexei Starovoitov <ast@kernel.org> Signed-off-by:

David S. Miller <davem@davemloft.net>

kernel/trace/bpf_trace.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -122,8 +122,8 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
		}

		/*
		* limited trace_printk()
		* only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed
		* Only limited trace_printk() conversion specifiers allowed:
		* %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s
		*/
		BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
		u64, arg2, u64, arg3)
		@@ -198,7 +198,8 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
		i++;
		}

		if (fmt[i] != 'd' && fmt[i] != 'u' && fmt[i] != 'x')
		if (fmt[i] != 'i' && fmt[i] != 'd' &&
		fmt[i] != 'u' && fmt[i] != 'x')
		return -EINVAL;
		fmt_cnt++;
		}

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