[PATCH v2 bpf-next 3/4] bpf: allow %pB in bpf_seq_printf() and bpf_trace_printk()
From: Song Liu <hidden>
Date: 2020-06-26 00:14:05
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [security & lsm] (security audit and enforcement using bpf), bpf [tracing], the rest, tracing · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, KP Singh, Matt Bobrowski, Song Liu, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
This makes it easy to dump stack trace in text. Signed-off-by: Song Liu <redacted> --- kernel/trace/bpf_trace.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 65fa62723e2f8..1cb90b0868817 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c@@ -376,7 +376,7 @@ static void bpf_trace_copy_string(char *buf, void *unsafe_ptr, char fmt_ptype, /* * Only limited trace_printk() conversion specifiers allowed: - * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pks %pus %s + * %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %pB %pks %pus %s */ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, u64, arg2, u64, arg3)
@@ -420,6 +420,11 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, goto fmt_str; } + if (fmt[i + 1] == 'B') { + i++; + goto fmt_next; + } + /* disallow any further format extensions */ if (fmt[i + 1] != 0 && !isspace(fmt[i + 1]) &&
@@ -479,7 +484,7 @@ BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1, #define __BPF_TP_EMIT() __BPF_ARG3_TP() #define __BPF_TP(...) \ __trace_printk(0 /* Fake ip */, \ - fmt, ##__VA_ARGS__) + fmt, ##__VA_ARGS__)\ #define __BPF_ARG1_TP(...) \ ((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \
@@ -636,7 +641,8 @@ BPF_CALL_5(bpf_seq_printf, struct seq_file *, m, char *, fmt, u32, fmt_size, if (fmt[i] == 'p') { if (fmt[i + 1] == 0 || fmt[i + 1] == 'K' || - fmt[i + 1] == 'x') { + fmt[i + 1] == 'x' || + fmt[i + 1] == 'B') { /* just kernel pointers */ params[fmt_cnt] = args[fmt_cnt]; fmt_cnt++;
--
2.24.1