tracing/osnoise: Replace kmalloc + copy_from_user with memdup_user_nul

Replace kmalloc() followed by copy_from_user() with memdup_user_nul() to
simplify and improve osnoise_cpus_write(). Remove the manual
NUL-termination.

No functional changes intended.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20251001130907.364673-2-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index dc734867f0fc441570cdca0b5d10477bc5af4b7b..26d0c99125f52a642398154f77c7e97839a470d6 100644 (file)
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -24,6 +24,7 @@
 #include <linux/sched/clock.h>
 #include <uapi/linux/sched/types.h>
 #include <linux/sched.h>
+#include <linux/string.h>
 #include "trace.h"
 
 #ifdef CONFIG_X86_LOCAL_APIC
@@ -2325,13 +2326,9 @@ osnoise_cpus_write(struct file *filp, const char __user *ubuf, size_t count,
        if (count < 1)
                return 0;
 
-       buf = kmalloc(count + 1, GFP_KERNEL);
-       if (!buf)
-               return -ENOMEM;
-
-       if (copy_from_user(buf, ubuf, count))
-               return -EFAULT;
-       buf[count] = '\0';
+       buf = memdup_user_nul(ubuf, count);
+       if (IS_ERR(buf))
+               return PTR_ERR(buf);
 
        if (!zalloc_cpumask_var(&osnoise_cpumask_new, GFP_KERNEL))
                return -ENOMEM;