From: Mark Langsdorf <mlangsdo@redhat.com> commit e483bb9a991bdae29a0caa4b3a6d002c968f94aa upstream. In cm_write(), buf is always freed when reaching the end of the function. If the requested count is less than table.length, the allocated buffer will be freed but subsequent calls to cm_write() will still try to access it. Remove the unconditional kfree(buf) at the end of the function and set the buf to NULL in the -EINVAL error path to match the rest of function. Fixes: 03d1571d9513 ("ACPI: custom_method: fix memory leaks") Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com> Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- drivers/acpi/custom_method.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/custom_method.c b/drivers/acpi/custom_method.c index 222ea3f12f41e..0bc0be355571b 100644 --- a/drivers/acpi/custom_method.c +++ b/drivers/acpi/custom_method.c @@ -50,6 +50,7 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, (*ppos + count < count) || (count > uncopied_bytes)) { kfree(buf); + buf = NULL; return -EINVAL; } @@ -71,7 +72,6 @@ static ssize_t cm_write(struct file *file, const char __user * user_buf, add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE); } - kfree(buf); return count; } -- 2.25.1