==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e48d80 of 1 bytes by task 1037 on cpu 1:
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x187/0x220 lib/vsprintf.c:721
 vsnprintf+0x532/0x890 lib/vsprintf.c:2874
 vscnprintf+0x41/0x90 lib/vsprintf.c:2939
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 dev_vprintk_emit+0x242/0x2a0 drivers/base/core.c:4917
 dev_printk_emit+0x84/0xb0 drivers/base/core.c:4928
 __dev_printk+0xf3/0x110 drivers/base/core.c:4940
 _dev_warn+0x9b/0xd0 drivers/base/core.c:4984
 hid_parser_main+0x6ff/0x750 drivers/hid/hid-core.c:-1
 hid_open_report+0x48e/0x7a0 drivers/hid/hid-core.c:1328
 hid_parse include/linux/hid.h:1133 [inline]
 hid_generic_probe+0x33/0x70 drivers/hid/hid-generic.c:66
 __hid_device_probe drivers/hid/hid-core.c:2724 [inline]
 hid_device_probe+0x2c5/0x490 drivers/hid/hid-core.c:2761
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x1bc/0x5a0 drivers/base/dd.c:657
 __driver_probe_device+0x121/0x190 drivers/base/dd.c:799
 driver_probe_device+0x37/0x2f0 drivers/base/dd.c:829
 __device_attach_driver+0x205/0x310 drivers/base/dd.c:957
 bus_for_each_drv+0x1c0/0x230 drivers/base/bus.c:462
 __device_attach+0x1c7/0x290 drivers/base/dd.c:1029
 device_initial_probe+0x1a/0x30 drivers/base/dd.c:1078
 bus_probe_device+0x143/0x1d0 drivers/base/bus.c:537
 device_add+0x5c9/0x770 drivers/base/core.c:3692
 hid_add_device+0x273/0x2f0 drivers/hid/hid-core.c:2907
 uhid_device_add_worker+0x2b/0xa0 drivers/hid/uhid.c:73
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xdd/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff88e48d80 of 8 bytes by task 12532 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 set_capacity_and_notify+0x14c/0x1f0 block/genhd.c:93
 loop_set_size+0x2e/0x70 drivers/block/loop.c:210
 loop_configure+0x8d3/0xa50 drivers/block/loop.c:1068
 lo_ioctl+0x559/0x15d0 drivers/block/loop.c:-1
 blkdev_ioctl+0x352/0x440 block/ioctl.c:704
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x19a8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000fffffd5b -> 0x3030303030323a43

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 12532 Comm: syz.4.3040 Not tainted 6.16.0-rc2-syzkaller-00082-gfb4d33ab452e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
 loop4: p1 p2 p3 < >
loop4: p1 size 242222080 extends beyond EOD, truncated
loop4: p2 start 4294967295 is beyond EOD, truncated