[PATCH] mtd: hyperbus: rpc-if: fix bug in rpcif_hb_remove

["George G. Davis" <george_davis@mentor.com>]

From: "George G. Davis" <davis.george@siemens.com>

The following KASAN BUG is observed when testing the rpc-if driver on
rcar-gen3:

root@rcar-gen3:~# modprobe -r rpc-if
[  101.930146] ==================================================================
[  101.937408] BUG: KASAN: slab-out-of-bounds in __lock_acquire+0x518/0x25d0
[  101.944240] Read of size 8 at addr ffff0004c5be2750 by task modprobe/664
[  101.950959]
[  101.952466] CPU: 2 PID: 664 Comm: modprobe Not tainted 5.14.0-rc1-00342-g1a1464d7aa31 #1
[  101.960578] Hardware name: Renesas H3ULCB board based on r8a77951 (DT)
[  101.967120] Call trace:
[  101.969580]  dump_backtrace+0x0/0x2c0
[  101.973275]  show_stack+0x1c/0x30
[  101.976616]  dump_stack_lvl+0x9c/0xd8
[  101.980301]  print_address_description.constprop.0+0x74/0x2b8
[  101.986071]  kasan_report+0x1f4/0x26c
[  101.989757]  __asan_load8+0x98/0xd4
[  101.993266]  __lock_acquire+0x518/0x25d0
[  101.997215]  lock_acquire.part.0+0x18c/0x360
[  102.001506]  lock_acquire+0x74/0x90
[  102.005013]  _raw_spin_lock_irq+0x98/0x130
[  102.009131]  __pm_runtime_disable+0x30/0x210
[  102.013427]  rpcif_hb_remove+0x5c/0x70 [rpc_if]
[  102.018001]  platform_remove+0x40/0x80
[  102.021771]  __device_release_driver+0x234/0x350
[  102.026412]  driver_detach+0x158/0x20c
[  102.030179]  bus_remove_driver+0xa0/0x140
[  102.034212]  driver_unregister+0x48/0x80
[  102.038153]  platform_driver_unregister+0x18/0x24
[  102.042879]  rpcif_platform_driver_exit+0x1c/0x34 [rpc_if]
[  102.048400]  __arm64_sys_delete_module+0x210/0x310
[  102.053212]  invoke_syscall+0x60/0x190
[  102.056986]  el0_svc_common+0x12c/0x144
[  102.060844]  do_el0_svc+0x88/0xac
[  102.064181]  el0_svc+0x24/0x3c
[  102.067257]  el0t_64_sync_handler+0x1a8/0x1b0
[  102.071634]  el0t_64_sync+0x198/0x19c
[  102.075315]
[  102.076815] Allocated by task 628:
[  102.080781]
[  102.082280] Last potentially related work creation:
[  102.087524]
[  102.089022] The buggy address belongs to the object at ffff0004c5be2000
[  102.089022]  which belongs to the cache kmalloc-2k of size 2048
[  102.101555] The buggy address is located 1872 bytes inside of
[  102.101555]  2048-byte region [ffff0004c5be2000, ffff0004c5be2800)
[  102.113486] The buggy address belongs to the page:
[  102.118409]
[  102.119908] Memory state around the buggy address:
[  102.124711]  ffff0004c5be2600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  102.131947]  ffff0004c5be2680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  102.139181] >ffff0004c5be2700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  102.146412]                                                  ^
[  102.152257]  ffff0004c5be2780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  102.159491]  ffff0004c5be2800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[  102.166723] ==================================================================

The above bug is caused by use of the wrong pointer in the
rpcif_disable_rpm() call. Fix the bug by using the correct pointer.

Fixes: e806241e03b7 ("mtd: hyperbus: add Renesas RPC-IF driver")
Signed-off-by: George G. Davis <davis.george@siemens.com>
---
 drivers/mtd/hyperbus/rpc-if.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/hyperbus/rpc-if.c b/drivers/mtd/hyperbus/rpc-if.c
index ecb050ba95cd..2806024b50ac 100644
--- a/drivers/mtd/hyperbus/rpc-if.c
+++ b/drivers/mtd/hyperbus/rpc-if.c
@@ -150,9 +150,9 @@ static int rpcif_hb_remove(struct platform_device *pdev)
 {
 	struct rpcif_hyperbus *hyperbus = platform_get_drvdata(pdev);
 	int error = hyperbus_unregister_device(&hyperbus->hbdev);
-	struct rpcif *rpc = dev_get_drvdata(pdev->dev.parent);
 
-	rpcif_disable_rpm(rpc);
+	rpcif_disable_rpm(&hyperbus->rpc);
+
 	return error;
 }
 
-- 
2.17.1