[PATCH 2/2] tracing/probes: Fix to set arg size and fmt after setting type from BTF

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhira...@kernel.org>

Since the BTF type setting updates probe_arg::type, the type size
calculation and setting print-fmt should be done after that.
Without this fix, the argument size and print-fmt can be wrong.

Fixes: b576e09701c7 ("tracing/probes: Support function parameters if BTF is 
available")
Cc: sta...@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
---
 kernel/trace/trace_probe.c |   25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index c6da5923e5b9..34289f9c6707 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -1172,18 +1172,6 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                trace_probe_log_err(ctx->offset + (t ? (t - arg) : 0), 
BAD_TYPE);
                goto out;
        }
-       parg->offset = *size;
-       *size += parg->type->size * (parg->count ?: 1);
-
-       ret = -ENOMEM;
-       if (parg->count) {
-               len = strlen(parg->type->fmttype) + 6;
-               parg->fmt = kmalloc(len, GFP_KERNEL);
-               if (!parg->fmt)
-                       goto out;
-               snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
-                        parg->count);
-       }
 
        code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
        if (!code)
@@ -1207,6 +1195,19 @@ static int traceprobe_parse_probe_arg_body(const char 
*argv, ssize_t *size,
                                goto fail;
                }
        }
+       parg->offset = *size;
+       *size += parg->type->size * (parg->count ?: 1);
+
+       if (parg->count) {
+               len = strlen(parg->type->fmttype) + 6;
+               parg->fmt = kmalloc(len, GFP_KERNEL);
+               if (!parg->fmt) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+               snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
+                        parg->count);
+       }
 
        ret = -EINVAL;
        /* Store operation */