EXT4-fs error (device loop8): __ext4_get_inode_loc_noinmem:4558: inode #2: block 4: comm kworker/u8:6: unable to read itable block
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff866975d8 of 8 bytes by task 14014 on cpu 0:
 prb_reserve+0x740/0xb60
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x168/0x690 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 mnt_warn_timestamp_expiry+0x1cd/0x210 fs/namespace.c:3014
 do_new_mount_fc fs/namespace.c:3495 [inline]
 do_new_mount+0x316/0x690 fs/namespace.c:3562
 path_mount+0x49b/0xb30 fs/namespace.c:3887
 do_mount fs/namespace.c:3900 [inline]
 __do_sys_mount fs/namespace.c:4111 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:4088
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4088
 x64_sys_call+0x2c84/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:166
 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

read to 0xffffffff866975d8 of 8 bytes by task 1875 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x46e/0x6c0 kernel/printk/printk_ringbuffer.c:2114
 prb_read_valid+0x3d/0x60 kernel/printk/printk_ringbuffer.c:2182
 printk_get_next_message+0xd8/0x530 kernel/printk/printk.c:2989
 console_emit_next_record kernel/printk/printk.c:3076 [inline]
 console_flush_all+0x2a7/0x790 kernel/printk/printk.c:3210
 __console_flush_and_unlock kernel/printk/printk.c:3269 [inline]
 console_unlock+0xb6/0x340 kernel/printk/printk.c:3309
 vprintk_emit+0x408/0x690 kernel/printk/printk.c:2432
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __ext4_error_inode+0x30b/0x400 fs/ext4/super.c:856
 __ext4_get_inode_loc_noinmem fs/ext4/inode.c:4557 [inline]
 ext4_write_inode+0x1e9/0x390 fs/ext4/inode.c:5254
 write_inode fs/fs-writeback.c:1525 [inline]
 __writeback_single_inode+0x340/0x850 fs/fs-writeback.c:1745
 writeback_sb_inodes+0x461/0xa30 fs/fs-writeback.c:1976
 wb_writeback+0x262/0x640 fs/fs-writeback.c:2156
 wb_do_writeback fs/fs-writeback.c:2303 [inline]
 wb_workfn+0x1a8/0x940 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x000000000000005b -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 1875 Comm: kworker/u8:6 Not tainted 6.14.0-rc7-syzkaller-00196-g88d324e69ea9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: writeback wb_workfn (flush-7:8)
==================================================================
kworker/u8:6: attempt to access beyond end of device
loop8: rw=145409, sector=0, nr_sectors = 8 limit=0
Buffer I/O error on dev loop8, logical block 0, lost sync page write
EXT4-fs (loop8): I/O error while writing superblock