loop4: detected capacity change from 0 to 256
==================================================================
BUG: KCSAN: data-race in data_push_tail / number

write to 0xffffffff86f2a3e4 of 1 bytes by task 21009 on cpu 0:
 number+0x7d0/0xa90 lib/vsprintf.c:562
 vsnprintf+0xa44/0xe20 lib/vsprintf.c:2862
 vscnprintf+0x42/0x80 lib/vsprintf.c:2902
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2137
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2251
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2297
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2327
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2337
 set_capacity_and_notify+0x178/0x1d0 block/genhd.c:90
 loop_set_size+0x2e/0x70 drivers/block/loop.c:237
 loop_configure+0xb01/0xca0 drivers/block/loop.c:1100
 lo_ioctl+0x688/0x12f0
 blkdev_ioctl+0x3a0/0x490 block/ioctl.c:615
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff86f2a3e0 of 8 bytes by task 21008 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2241
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2297
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2327
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2337
 set_capacity_and_notify+0x178/0x1d0 block/genhd.c:90
 loop_set_size+0x2e/0x70 drivers/block/loop.c:237
 loop_configure+0xb01/0xca0 drivers/block/loop.c:1100
 lo_ioctl+0x688/0x12f0
 blkdev_ioctl+0x3a0/0x490 block/ioctl.c:615
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000100000d9f -> 0x0a3635363532206f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21008 Comm: syz-executor.4 Not tainted 6.3.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
==================================================================
FAT-fs (loop4): Unrecognized mount option "Wni_" or missing value