[PATCH] tracing: check the return value of kstrdup()

[PATCH] tracing: check the return value of kstrdup()

[xkernel]

kstrdup() returns NULL when some internal memory errors happen, it is
better to check the return value of it. The code is under Linux-5.15.

Signed-off-by: xkernel <xkernel.wang@foxmail.com>
---
 kernel/trace/trace_boot.c   | 4 ++++
 kernel/trace/trace_uprobe.c | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 8d252f6..0580287 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -430,6 +430,8 @@ trace_boot_init_histograms(struct trace_event_file *file,
 		/* All digit started node should be instances. */
 		if (trace_boot_compose_hist_cmd(node, buf, size) == 0) {
 			tmp = kstrdup(buf, GFP_KERNEL);
+			if (!tmp)
+				return;
 			if (trigger_process_regex(file, buf) < 0)
 				pr_err("Failed to apply hist trigger: %s\n", tmp);
 			kfree(tmp);
@@ -439,6 +441,8 @@ trace_boot_init_histograms(struct trace_event_file *file,
 	if (xbc_node_find_subkey(hnode, "keys")) {
 		if (trace_boot_compose_hist_cmd(hnode, buf, size) == 0) {
 			tmp = kstrdup(buf, GFP_KERNEL);
+			if (!tmp)
+				return;
 			if (trigger_process_regex(file, buf) < 0)
 				pr_err("Failed to apply hist trigger: %s\n", tmp);
 			kfree(tmp);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 225ce56..173ff0f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1618,6 +1618,11 @@ create_local_trace_uprobe(char *name, unsigned long offs,
 	tu->path = path;
 	tu->ref_ctr_offset = ref_ctr_offset;
 	tu->filename = kstrdup(name, GFP_KERNEL);
+	if (!tu->filename) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
 	init_trace_event_call(tu);
 
 	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
-- 

Re: [PATCH] tracing: check the return value of kstrdup()

[Xiaoke Wang]

Note: Compare with the last email, this one is using my full name.
And I am sorry that yesterday I did not notice the bugs in trace_boot.c had been
already patched.
kstrdup() returns NULL when some internal memory errors happen, it is
better to check the return value of it.

Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
---
 kernel/trace/trace_uprobe.c | 5 +++++
 1 files changed, 5 insertions(+)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 225ce56..173ff0f 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1618,6 +1618,11 @@ create_local_trace_uprobe(char *name, unsigned long offs,
 	tu->path = path;
 	tu->ref_ctr_offset = ref_ctr_offset;
 	tu->filename = kstrdup(name, GFP_KERNEL);
+	if (!tu->filename) {
+		ret = -ENOMEM;
+		goto error;
+	}
+
 	init_trace_event_call(tu);
 
 	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;
-- 

Re: [PATCH] tracing: check the return value of kstrdup()

[Steven Rostedt]

On Mon, 13 Dec 2021 15:59:04 +0800
Xiaoke Wang <xkernel.wang@foxmail.com> wrote:

> Note: Compare with the last email, this one is using my full name.
> And I am sorry that yesterday I did not notice the bugs in trace_boot.c had been
> already patched.
> kstrdup() returns NULL when some internal memory errors happen, it is
> better to check the return value of it.

Can you please resend this as a normal patch, and not a reply to this email
thread.

Thank you,

-- Steve


> 
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
> ---
>  kernel/trace/trace_uprobe.c | 5 +++++
>  1 files changed, 5 insertions(+)
> 
> diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> index 225ce56..173ff0f 100644
> --- a/kernel/trace/trace_uprobe.c
> +++ b/kernel/trace/trace_uprobe.c
> @@ -1618,6 +1618,11 @@ create_local_trace_uprobe(char *name, unsigned long offs,
>  	tu->path = path;
>  	tu->ref_ctr_offset = ref_ctr_offset;
>  	tu->filename = kstrdup(name, GFP_KERNEL);
> +	if (!tu->filename) {
> +		ret = -ENOMEM;
> +		goto error;
> +	}
> +
>  	init_trace_event_call(tu);
>  
>  	ptype = is_ret_probe(tu) ? PROBE_PRINT_RETURN : PROBE_PRINT_NORMAL;