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BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff8608a348 of 8 bytes by task 27381 on cpu 0:
 data_alloc+0x291/0x2c0 kernel/printk/printk_ringbuffer.c:1096
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2266
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2326
 dev_vprintk_emit+0x1df/0x210 drivers/base/core.c:4951
 dev_printk_emit+0x82/0xb0 drivers/base/core.c:4962
 __dev_printk+0xf6/0x110 drivers/base/core.c:4974
 _dev_warn+0x99/0xc0 drivers/base/core.c:5018
 hid_parser_main+0x622/0x680 drivers/hid/hid-core.c:632
 hid_open_report+0x4e6/0x800 drivers/hid/hid-core.c:1276
 hid_parse include/linux/hid.h:1118 [inline]
 hid_generic_probe+0x33/0x70 drivers/hid/hid-generic.c:63
 __hid_device_probe drivers/hid/hid-core.c:2633 [inline]
 hid_device_probe+0x220/0x370 drivers/hid/hid-core.c:2670
 really_probe+0x1cf/0x5d0 drivers/base/dd.c:656
 __driver_probe_device+0x12d/0x200 drivers/base/dd.c:798
 driver_probe_device+0x38/0x2f0 drivers/base/dd.c:828
 __device_attach_driver+0x216/0x320 drivers/base/dd.c:956
 bus_for_each_drv+0x1cd/0x240 drivers/base/bus.c:457
 __device_attach+0x1c7/0x290 drivers/base/dd.c:1028
 device_initial_probe+0x1a/0x20 drivers/base/dd.c:1077
 bus_probe_device+0x141/0x1d0 drivers/base/bus.c:532
 device_add+0x5e2/0x790 drivers/base/core.c:3721
 hid_add_device+0x26e/0x2f0 drivers/hid/hid-core.c:2816
 uhid_device_add_worker+0x2b/0xa0 drivers/hid/uhid.c:73
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x730 kernel/workqueue.c:3393
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffffffff8608a348 of 8 bytes by task 27662 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline]
 prb_reserve+0x235/0xb60 kernel/printk/printk_ringbuffer.c:1619
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2266
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2326
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2360
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2370
 set_capacity_and_notify+0xff/0x160 block/genhd.c:86
 loop_set_size+0x2e/0x70 drivers/block/loop.c:235
 loop_configure+0xae8/0xc80 drivers/block/loop.c:1098
 lo_ioctl+0x682/0x1330
 blkdev_ioctl+0x35f/0x450 block/ioctl.c:676
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xd3/0x150 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x1581/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000fed40 -> 0x00000000001c45e0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27662 Comm: syz-executor.2 Not tainted 6.10.0-rc2-syzkaller-00222-gd30d0e49da71 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
==================================================================
loop2: detected capacity change from 0 to 256