scsi: ufs: core: Fix a race condition related to the "hid" attribute group

ufs_sysfs_add_nodes() is called concurrently with ufs_get_device_desc().
This may cause the following code to be called before
ufs_sysfs_add_nodes():

	sysfs_update_group(&hba->dev->kobj, &ufs_sysfs_hid_group);

If this happens, ufs_sysfs_add_nodes() triggers a kernel warning and
fails. Fix this by calling ufs_sysfs_add_nodes() before SCSI LUNs are
scanned since the sysfs_update_group() call happens from the context of
thread that executes ufshcd_async_scan(). This patch fixes the following
kernel warning:

sysfs: cannot create duplicate filename '/devices/platform/3c2d0000.ufs/hid'
Workqueue: async async_run_entry_fn
Call trace:
 dump_backtrace+0xfc/0x17c
 show_stack+0x18/0x28
 dump_stack_lvl+0x40/0x104
 dump_stack+0x18/0x3c
 sysfs_warn_dup+0x6c/0xc8
 internal_create_group+0x1c8/0x504
 sysfs_create_groups+0x38/0x9c
 ufs_sysfs_add_nodes+0x20/0x58
 ufshcd_init+0x1114/0x134c
 ufshcd_pltfrm_init+0x728/0x7d8
 ufs_google_probe+0x30/0x84
 platform_probe+0xa0/0xe0
 really_probe+0x114/0x454
 __driver_probe_device+0xa4/0x160
 driver_probe_device+0x44/0x23c
 __device_attach_driver+0x15c/0x1f4
 bus_for_each_drv+0x10c/0x168
 __device_attach_async_helper+0x80/0xf8
 async_run_entry_fn+0x4c/0x17c
 process_one_work+0x26c/0x65c
 worker_thread+0x33c/0x498
 kthread+0x110/0x134
 ret_from_fork+0x10/0x20
ufshcd 3c2d0000.ufs: ufs_sysfs_add_nodes: sysfs groups creation failed (err = -17)

Cc: Daniel Lee <chullee@google.com>
Fixes: bb7663dec67b ("scsi: ufs: sysfs: Make HID attributes visible")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251014200118.3390839-2-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 9ca27de4767a18a2e02fae862c09ccd6743b7ebb..322641457a2d4201ffa3f25dfa6b7985652a7193 100644 (file)
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -10891,8 +10891,8 @@ initialized:
        if (err)
                goto out_disable;
 
-       async_schedule(ufshcd_async_scan, hba);
        ufs_sysfs_add_nodes(hba->dev);
+       async_schedule(ufshcd_async_scan, hba);
 
        device_enable_async_suspend(dev);
        ufshcd_pm_qos_init(hba);