==================================================================
BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff86d0fc18 of 88 bytes by task 31936 on cpu 0:
 prb_reserve+0x6fb/0xaf0 kernel/printk/printk_ringbuffer.c:1693
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 rfkill_fop_release+0x14d/0x150 net/rfkill/core.c:1353
 __fput+0x29e/0x630 fs/file_table.c:512
 ____fput+0x1c/0x30 fs/file_table.c:540
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:70 [inline]
 exit_to_user_mode_loop+0x1e4/0x8c0 kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x23c/0x3c0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86d0fc18 of 8 bytes by task 31942 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:500 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:2017 [inline]
 _prb_read_valid+0x325/0x930 kernel/printk/printk_ringbuffer.c:2174
 prb_first_valid_seq+0x35/0x70 kernel/printk/printk_ringbuffer.c:2302
 devkmsg_open+0x174/0x1b0 kernel/printk/printk.c:945
 memory_open+0xfa/0x120 drivers/char/mem.c:727
 chrdev_open+0x2eb/0x3a0 fs/char_dev.c:411
 do_dentry_open+0x49f/0xa60 fs/open.c:947
 vfs_open+0x37/0x1e0 fs/open.c:1052
 do_open fs/namei.c:4700 [inline]
 path_openat+0x1b39/0x2000 fs/namei.c:4859
 do_file_open+0x16c/0x290 fs/namei.c:4888
 do_sys_openat2+0xa0/0x130 fs/open.c:1368
 do_sys_open fs/open.c:1374 [inline]
 __do_sys_openat fs/open.c:1390 [inline]
 __se_sys_openat fs/open.c:1385 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1385
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000003673 -> 0x0000000000005673

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 31942 Comm: fido_id Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================
fido_id[31942]: Failed to open report descriptor at '/sys/devices/virtual/misc/uhid/report_descriptor': No such file or directory