2021-12-12 15:36:56

by Xiaoke Wang

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

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 <[email protected]>
---
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;
--

2021-12-13 07:59:24

by Xiaoke Wang

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

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 <[email protected]>
---
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;
--

2021-12-13 16:52:12

by Steven Rostedt

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

On Mon, 13 Dec 2021 15:59:04 +0800
Xiaoke Wang <[email protected]> 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 <[email protected]>
> ---
> 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;