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Subject[PATCH v4 bpf-next 3/4] bpf: allow %pB in bpf_seq_printf() and bpf_trace_printk()
Date
This makes it easy to dump stack trace in text.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
kernel/trace/bpf_trace.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 977ba3b6f6c64..1d874d8e4384b 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]) &&
@@ -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
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