asus-laptop: Fix an uninitialized variable

commit 6c683c6887e4addcd6bd1ddce08cafccb0a21e32 upstream.

The value returned by acpi_evaluate_integer() is not checked,
but the result is not always successful, so it is necessary to
add a check of the returned value.

If the result remains negative during three iterations of the loop,
then the uninitialized variable 'val' will be used in the clamp_val()
macro, so it must be initialized with the current value of the 'curr'
variable.

In this case, the algorithm should be less noisy.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: b23910c2194e ("asus-laptop: Pegatron Lucid accelerometer")
Cc: stable@vger.kernel.org
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Link: https://lore.kernel.org/r/20250403122603.18172-1-arefev@swemel.ru
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/platform/x86/asus-laptop.c b/drivers/platform/x86/asus-laptop.c
index 472af7edf0af31c5f0003ac6c89584a6bb95581b..bfed040bce6c832ae67d5697a2deb70ed1a38a95 100644 (file)
--- a/drivers/platform/x86/asus-laptop.c
+++ b/drivers/platform/x86/asus-laptop.c
@@ -428,11 +428,14 @@ static int asus_pega_lucid_set(struct asus_laptop *asus, int unit, bool enable)
 
 static int pega_acc_axis(struct asus_laptop *asus, int curr, char *method)
 {
+       unsigned long long val = (unsigned long long)curr;
+       acpi_status status;
        int i, delta;
-       unsigned long long val;
-       for (i = 0; i < PEGA_ACC_RETRIES; i++) {
-               acpi_evaluate_integer(asus->handle, method, NULL, &val);
 
+       for (i = 0; i < PEGA_ACC_RETRIES; i++) {
+               status = acpi_evaluate_integer(asus->handle, method, NULL, &val);
+               if (ACPI_FAILURE(status))
+                       continue;
                /* The output is noisy.  From reading the ASL
                 * dissassembly, timeout errors are returned with 1's
                 * in the high word, and the lack of locking around