scsi: ufs: core: Fix NULL pointer dereference

Calling ufshcd_rpm_{get/put}_sync() prior to ufshcd_scsi_add_wlus() being
called will trigger a NULL pointer dereference. This is because
hba->sdev_ufs_device is initialized in ufshcd_scsi_add_wlus().

    Unable to handle kernel NULL pointer dereference at virtual address
    0000000000000348
    Mem abort info:
      ESR = 0x96000004
      EC = 0x25: DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
      FSC = 0x04: level 0 translation fault
    Data abort info:
      ISV = 0, ISS = 0x00000004
      CM = 0, WnR = 0
    [0000000000000348] user address but active_mm is swapper
    Internal error: Oops: 96000004 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 91 Comm: kworker/u16:1 Not tainted 5.15.0-rc1-beanhuo-linaro-1423
    Hardware name: MicronRB (DT)
    Workqueue: events_unbound async_run_entry_fn
    pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
    pc : pm_runtime_drop_link+0x128/0x338
    lr : ufshpb_get_dev_info+0x8c/0x148
    sp : ffff800012573c10
    x29: ffff800012573c10 x28: 0000000000000000 x27: 0000000000000003
    x26: ffff000001d21298 x25: 000000005abcea60 x24: ffff800011d89000
    x23: 0000000000000001 x22: ffff000001d21880 x21: ffff000001ec9300
    x20: 0000000000000004 x19: 0000000000000198 x18: ffffffffffffffff
    x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000041400
    x14: 5eee00201100200a x13: 000000000000bb03 x12: 0000000000000000
    x11: 0000000000000100 x10: 0200000000000000 x9 : bb0000021a162c01
    x8 : 0302010021021003 x7 : 0000000000000000 x6 : ffff800012573af0
    x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000200
    x2 : 0000000000000348 x1 : 0000000000000348 x0 : ffff80001095308c
    Call trace:
     pm_runtime_drop_link+0x128/0x338
     ufshpb_get_dev_info+0x8c/0x148
     ufshcd_probe_hba+0xda0/0x11b8
     ufshcd_async_scan+0x34/0x330
     async_run_entry_fn+0x38/0x180
     process_one_work+0x1f4/0x498
     worker_thread+0x48/0x480
     kthread+0x140/0x158
     ret_from_fork+0x10/0x20
    Code: 88027c01 35ffffa2 17fff6c4 f9800051 (885f7c40)
    ---[ end trace 2ba541335f595c95 ]

ufshpb_get_dev_info() is only called during asynchronous scanning and at
that time pm_runtime_get_sync() has been called:

    ...
    /* Hold auto suspend until async scan completes */
    pm_runtime_get_sync(dev);
    atomic_set(&hba->scsi_block_reqs_cnt, 0);
    ...
    ufshcd_async_scan()
        ufshcd_probe_hba(hba, true);
            ufshcd_device_params_init(hba);
                ufshpb_get_dev_info();
    ...
        pm_runtime_put_sync(hba->dev);

Remove ufshcd_rpm_{get/put}_sync() from ufshpb_get_dev_info() to fix this
problem.

Link: https://lore.kernel.org/r/20210929200640.828611-2-huobean@gmail.com
Fixes: 351b3a849ac7 ("scsi: ufs: ufshpb: Use proper power management API")
Signed-off-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/drivers/scsi/ufs/ufshpb.c b/drivers/scsi/ufs/ufshpb.c
index 9ea639bf6a59..33a38c06a296 100644
--- a/drivers/scsi/ufs/ufshpb.c
+++ b/drivers/scsi/ufs/ufshpb.c
@@ -2877,11 +2877,8 @@ void ufshpb_get_dev_info(struct ufs_hba *hba, u8 *desc_buf)
 	if (version == HPB_SUPPORT_LEGACY_VERSION)
 		hpb_dev_info->is_legacy = true;
 
-	ufshcd_rpm_get_sync(hba);
 	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
 		QUERY_ATTR_IDN_MAX_HPB_SINGLE_CMD, 0, 0, &max_hpb_single_cmd);
-	ufshcd_rpm_put_sync(hba);
-
 	if (ret)
 		dev_err(hba->dev, "%s: idn: read max size of single hpb cmd query request failed",
 			__func__);