From: Yongxin Liu <[email protected]>

The intel_pmc_ipc() function uses ACPI_ALLOCATE_BUFFER to allocate memory
for the ACPI evaluation result but never frees it, causing a 192-byte
memory leak on each call.

This leak is triggered during network interface initialization when the
stmmac driver calls intel_mac_finish() -> intel_pmc_ipc().

  unreferenced object 0xffff96a848d6ea80 (size 192):
    comm "dhcpcd", pid 541, jiffies 4294684345
    hex dump (first 32 bytes):
      04 00 00 00 05 00 00 00 98 ea d6 48 a8 96 ff ff  ...........H....
      00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
    backtrace (crc b1564374):
      kmemleak_alloc+0x2d/0x40
      __kmalloc_noprof+0x2fa/0x730
      acpi_ut_initialize_buffer+0x83/0xc0
      acpi_evaluate_object+0x29a/0x2f0
      intel_pmc_ipc+0xfd/0x170
      intel_mac_finish+0x168/0x230
      stmmac_mac_finish+0x3d/0x50
      phylink_major_config+0x22b/0x5b0
      phylink_mac_initial_config.constprop.0+0xf1/0x1b0
      phylink_start+0x8e/0x210
      __stmmac_open+0x12c/0x2b0
      stmmac_open+0x23c/0x380
      __dev_open+0x11d/0x2c0
      __dev_change_flags+0x1d2/0x250
      netif_change_flags+0x2b/0x70
      dev_change_flags+0x40/0xb0

Add kfree() to properly release the allocated buffer.

Cc: [email protected]
Fixes: 7e2f7e25f6ff ("arch: x86: add IPC mailbox accessor function and add SoC 
register access")
Signed-off-by: Yongxin Liu <[email protected]>
---
 arch/x86/platform/intel/pmc_ipc.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/x86/platform/intel/pmc_ipc.c 
b/arch/x86/platform/intel/pmc_ipc.c
index a96234982710..85ec9e0d8312 100644
--- a/arch/x86/platform/intel/pmc_ipc.c
+++ b/arch/x86/platform/intel/pmc_ipc.c
@@ -28,7 +28,7 @@ int intel_pmc_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
        };
        struct acpi_object_list arg_list = { PMC_IPCS_PARAM_COUNT, params };
        union acpi_object *obj;
-       int status;
+       int status, ret = 0;
 
        if (!ipc_cmd || !rbuf)
                return -EINVAL;
@@ -56,18 +56,22 @@ int intel_pmc_ipc(struct pmc_ipc_cmd *ipc_cmd, u32 *rbuf)
        if (obj && obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) {
                const union acpi_object *objs = obj->package.elements;
 
-               if ((u8)objs[0].integer.value != 0)
-                       return -EINVAL;
+               if ((u8)objs[0].integer.value != 0) {
+                       ret = -EINVAL;
+                       goto out;
+               }
 
                rbuf[0] = objs[1].integer.value;
                rbuf[1] = objs[2].integer.value;
                rbuf[2] = objs[3].integer.value;
                rbuf[3] = objs[4].integer.value;
        } else {
-               return -EINVAL;
+               ret = -EINVAL;
        }
 
-       return 0;
+out:
+       kfree(obj);
+       return ret;
 }
 EXPORT_SYMBOL(intel_pmc_ipc);
 
-- 
2.49.1

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