HID: intel-ish-hid: Fix -Wcast-function-type-strict in devm_ishtp_alloc_workqueue()

Clang warns (or errors with CONFIG_WERROR=y / W=e):

  drivers/hid/intel-ish-hid/ipc/ipc.c:935:36: error: cast from 'void (*)(struct workqueue_struct *)' to 'void (*)(void *)' converts to incompatible function type [-Werror,-Wcast-function-type-strict]
    935 |         if (devm_add_action_or_reset(dev, (void (*)(void *))destroy_workqueue,
        |                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  include/linux/device/devres.h:168:34: note: expanded from macro 'devm_add_action_or_reset'
    168 |         __devm_add_action_or_ireset(dev, action, data, #action)
        |                                         ^~~~~~

This warning is pointing out a kernel control flow integrity (kCFI /
CONFIG_CFI=y) violation will occur due to this function cast when the
destroy_workqueue() is indirectly called via devm_action_release()
because the prototype of destroy_workqueue() does not match the
prototype of (*action)().

Use a local function with the correct prototype to wrap
destroy_workqueue() to resolve the warning and CFI violation.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202510190103.qTZvfdjj-lkp@intel.com/
Closes: https://github.com/ClangBuiltLinux/linux/issues/2139
Fixes: 0d30dae38fe0 ("HID: intel-ish-hid: Use dedicated unbound workqueues to prevent resume blocking")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Zhang Lixu <lixu.zhang@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-ish-hid/ipc/ipc.c
index 59355e4a61f829949f7b2f2ef885bf1414823156..abf9c9a31c396590bf2b35b0a690004fe5b46d2b 100644 (file)
--- a/drivers/hid/intel-ish-hid/ipc/ipc.c
+++ b/drivers/hid/intel-ish-hid/ipc/ipc.c
@@ -924,6 +924,11 @@ static const struct ishtp_hw_ops ish_hw_ops = {
        .dma_no_cache_snooping = _dma_no_cache_snooping
 };
 
+static void ishtp_free_workqueue(void *wq)
+{
+       destroy_workqueue(wq);
+}
+
 static struct workqueue_struct *devm_ishtp_alloc_workqueue(struct device *dev)
 {
        struct workqueue_struct *wq;
@@ -932,8 +937,7 @@ static struct workqueue_struct *devm_ishtp_alloc_workqueue(struct device *dev)
        if (!wq)
                return NULL;
 
-       if (devm_add_action_or_reset(dev, (void (*)(void *))destroy_workqueue,
-                                    wq))
+       if (devm_add_action_or_reset(dev, ishtp_free_workqueue, wq))
                return NULL;
 
        return wq;