loop1: detected capacity change from 0 to 512
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff86eb6d95 of 1 bytes by task 9588 on cpu 0:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x200 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe20 lib/vsprintf.c:2819
 va_format lib/vsprintf.c:1683 [inline]
 pointer+0x8a1/0xd10 lib/vsprintf.c:2450
 vsnprintf+0x861/0xe20 lib/vsprintf.c:2823
 vscnprintf+0x42/0x80 lib/vsprintf.c:2925
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2124
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2238
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 _fat_msg+0xa2/0xd0 fs/fat/misc.c:62
 parse_options fs/fat/inode.c:1361 [inline]
 fat_fill_super+0x23f2/0x28e0 fs/fat/inode.c:1646
 vfat_fill_super+0x30/0x40 fs/fat/namei_vfat.c:1200
 mount_bdev+0x185/0x1f0 fs/super.c:1650
 vfat_mount+0x31/0x40 fs/fat/namei_vfat.c:1207
 legacy_get_tree+0x74/0xd0 fs/fs_context.c:662
 vfs_get_tree+0x51/0x1b0 fs/super.c:1771
 do_new_mount+0x203/0x660 fs/namespace.c:3337
 path_mount+0x496/0xb30 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff86eb6d90 of 8 bytes by task 9590 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:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 set_capacity_and_notify+0x11d/0x170 block/genhd.c:86
 loop_set_size+0x2e/0x70 drivers/block/loop.c:237
 loop_configure+0xaf9/0xca0 drivers/block/loop.c:1100
 lo_ioctl+0x682/0x12e0
 blkdev_ioctl+0x375/0x460 block/ioctl.c:633
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x00000001000095f9 -> 0x756e6f6e6e22206e

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9590 Comm: syz-executor.1 Not tainted 6.7.0-rc5-syzkaller-00270-g0e389834672c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
EXT4-fs (loop1): orphan cleanup on readonly fs
Quota error (device loop1): v2_read_header: Failed header read: expected=8 got=4
EXT4-fs warning (device loop1): ext4_enable_quotas:7107: Failed to enable quota tracking (type=0, err=-22, ino=3). Please run e2fsck to fix.
EXT4-fs (loop1): Cannot turn on quotas: error -22
EXT4-fs error (device loop1): ext4_validate_block_bitmap:441: comm syz-executor.1: bg 0: block 64: padding at end of block bitmap is not set
EXT4-fs error (device loop1) in ext4_mb_clear_bb:6517: Corrupt filesystem
EXT4-fs (loop1): 1 orphan inode deleted
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback.