[PATCH v4 6/7] tracing: uprobe-event: Allocate string buffers from heap

[Masami Hiramatsu (Google)]

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

Allocate temporary string buffers for parsing uprobe-events
from heap instead of stack.

Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rost...@goodmis.org>
---
 Changes in v3:
  - Split #include sorting.
 Changes in v2:
  - Sort #include alphabetically.
  - Add fail_mem label for handling ENOMEM error.
---
 kernel/trace/trace_uprobe.c |   28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 872dce092e46..8b0bcc0d8f41 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -8,6 +8,7 @@
 #define pr_fmt(fmt)    "trace_uprobe: " fmt
 
 #include <linux/bpf-cgroup.h>
+#include <linux/cleanup.h>
 #include <linux/ctype.h>
 #include <linux/filter.h>
 #include <linux/module.h>
@@ -19,6 +20,7 @@
 #include <linux/uaccess.h>
 #include <linux/uprobes.h>
 
+#include "trace.h"
 #include "trace_dynevent.h"
 #include "trace_probe.h"
 #include "trace_probe_tmpl.h"
@@ -537,15 +539,15 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
  */
 static int __trace_uprobe_create(int argc, const char **argv)
 {
-       struct trace_uprobe *tu;
        const char *event = NULL, *group = UPROBE_EVENT_SYSTEM;
        char *arg, *filename, *rctr, *rctr_end, *tmp;
-       char buf[MAX_EVENT_NAME_LEN];
-       char gbuf[MAX_EVENT_NAME_LEN];
-       enum probe_print_type ptype;
-       struct path path;
        unsigned long offset, ref_ctr_offset;
+       char *gbuf __free(kfree) = NULL;
+       char *buf __free(kfree) = NULL;
+       enum probe_print_type ptype;
+       struct trace_uprobe *tu;
        bool is_return = false;
+       struct path path;
        int i, ret;
 
        ref_ctr_offset = 0;
@@ -653,6 +655,10 @@ static int __trace_uprobe_create(int argc, const char 
**argv)
        /* setup a probe */
        trace_probe_log_set_index(0);
        if (event) {
+               gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+               if (!gbuf)
+                       goto fail_mem;
+
                ret = traceprobe_parse_event_name(&event, &group, gbuf,
                                                  event - argv[0]);
                if (ret)
@@ -664,15 +670,16 @@ static int __trace_uprobe_create(int argc, const char 
**argv)
                char *ptr;
 
                tail = kstrdup(kbasename(filename), GFP_KERNEL);
-               if (!tail) {
-                       ret = -ENOMEM;
-                       goto fail_address_parse;
-               }
+               if (!tail)
+                       goto fail_mem;
 
                ptr = strpbrk(tail, ".-_");
                if (ptr)
                        *ptr = '\0';
 
+               buf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
+               if (!buf)
+                       goto fail_mem;
                snprintf(buf, MAX_EVENT_NAME_LEN, "%c_%s_0x%lx", 'p', tail, 
offset);
                event = buf;
                kfree(tail);
@@ -724,6 +731,9 @@ static int __trace_uprobe_create(int argc, const char 
**argv)
        trace_probe_log_clear();
        return ret;
 
+fail_mem:
+       ret = -ENOMEM;
+
 fail_address_parse:
        trace_probe_log_clear();
        path_put(&path);