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BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff86a9eb88 of 8 bytes by task 7015 on cpu 1:
 data_alloc+0x27e/0x2b0 kernel/printk/printk_ringbuffer.c:1085
 prb_reserve+0x8da/0xbb0 kernel/printk/printk_ringbuffer.c:1549
 vprintk_store+0x3e9/0x9b0 kernel/printk/printk.c:2005
 vprintk_emit+0xca/0x360 kernel/printk/printk.c:2057
 dev_vprintk_emit+0x1c6/0x1ea drivers/base/core.c:4283
 dev_printk_emit+0x6a/0x8c drivers/base/core.c:4294
 __dev_printk+0xfa/0x103 drivers/base/core.c:4306
 _dev_info+0x76/0x96 drivers/base/core.c:4352
 hub_port_init+0x7bc/0x1890 drivers/usb/core/hub.c:4647
 hub_port_connect drivers/usb/core/hub.c:5155 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
 port_event drivers/usb/core/hub.c:5509 [inline]
 hub_event+0x1a33/0x2b60 drivers/usb/core/hub.c:5591
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffffffff86a9eb88 of 8 bytes by task 5 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:477 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:771 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:917 [inline]
 prb_reserve+0x20c/0xbb0 kernel/printk/printk_ringbuffer.c:1499
 vprintk_store+0x3e9/0x9b0 kernel/printk/printk.c:2005
 vprintk_emit+0xca/0x360 kernel/printk/printk.c:2057
 dev_vprintk_emit+0x1c6/0x1ea drivers/base/core.c:4283
 dev_printk_emit+0x6a/0x8c drivers/base/core.c:4294
 __dev_printk+0xfa/0x103 drivers/base/core.c:4306
 _dev_err+0x76/0x96 drivers/base/core.c:4349
 snd_usb_create_stream+0x261/0x340 sound/usb/card.c:143
 snd_usb_create_streams sound/usb/card.c:278 [inline]
 usb_audio_probe+0x887/0x1810 sound/usb/card.c:802
 usb_probe_interface+0x461/0x6a0 drivers/usb/core/driver.c:396
 really_probe+0x4ee/0xb70 drivers/base/dd.c:565
 driver_probe_device+0xcc/0x120 drivers/base/dd.c:745
 __device_attach_driver+0x255/0x290 drivers/base/dd.c:851
 bus_for_each_drv+0xd8/0x140 drivers/base/bus.c:431
 __device_attach+0x1a0/0x290 drivers/base/dd.c:919
 device_initial_probe+0x16/0x20 drivers/base/dd.c:966
 bus_probe_device+0x7a/0x140 drivers/base/bus.c:491
 device_add+0xcb2/0xe50 drivers/base/core.c:3091
 usb_set_configuration+0x10cd/0x13b0 drivers/usb/core/message.c:2164
 usb_generic_driver_probe+0x54/0xd0 drivers/usb/core/generic.c:238
 usb_probe_device+0xfb/0x1a0 drivers/usb/core/driver.c:293
 really_probe+0x4ee/0xb70 drivers/base/dd.c:565
 driver_probe_device+0xcc/0x120 drivers/base/dd.c:745
 __device_attach_driver+0x255/0x290 drivers/base/dd.c:851
 bus_for_each_drv+0xd8/0x140 drivers/base/bus.c:431
 __device_attach+0x1a0/0x290 drivers/base/dd.c:919
 device_initial_probe+0x16/0x20 drivers/base/dd.c:966
 bus_probe_device+0x7a/0x140 drivers/base/bus.c:491
 device_add+0xcb2/0xe50 drivers/base/core.c:3091
 usb_new_device+0x719/0xc80 drivers/usb/core/hub.c:2555
 hub_port_connect drivers/usb/core/hub.c:5223 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5363 [inline]
 port_event drivers/usb/core/hub.c:5509 [inline]
 hub_event+0x1d25/0x2b60 drivers/usb/core/hub.c:5591
 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275
 worker_thread+0x635/0xb90 kernel/workqueue.c:2421
 kthread+0x1fd/0x220 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.10.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
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