kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=209, nr_sectors = 8 limit=128
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c7a3a0 of 8 bytes by task 11264 on cpu 0:
 data_alloc+0x310/0x390 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8d6/0xad0 kernel/printk/printk_ringbuffer.c:1727
 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
 fserror_report+0x427/0x500 fs/fserror.c:182
 fserror_report_metadata include/linux/fserror.h:67 [inline]
 __ext4_error+0x152/0x2e0 fs/ext4/super.c:834
 ext4_orphan_get+0x189/0x430 fs/ext4/ialloc.c:1400
 ext4_orphan_cleanup+0x5fa/0x9f0 fs/ext4/orphan.c:465
 __ext4_fill_super fs/ext4/super.c:5701 [inline]
 ext4_fill_super+0x3408/0x37c0 fs/ext4/super.c:5824
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1694
 get_tree_bdev+0x1f/0x30 fs/super.c:1717
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5856
 vfs_get_tree+0x57/0x1d0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3834
 path_mount+0x4d0/0xbc0 fs/namespace.c:4154
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4360
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4360
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86c7a3a0 of 16 bytes by task 22751 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1982 [inline]
 _prb_read_valid+0x1b6/0x950 kernel/printk/printk_ringbuffer.c:2173
 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245
 printk_get_next_message+0xea/0x560 kernel/printk/printk.c:3052
 console_emit_next_record kernel/printk/printk.c:3137 [inline]
 console_flush_one_record kernel/printk/printk.c:3269 [inline]
 console_flush_all+0x2cd/0x6c0 kernel/printk/printk.c:3343
 __console_flush_and_unlock kernel/printk/printk.c:3373 [inline]
 console_unlock+0xa1/0x280 kernel/printk/printk.c:3413
 vprintk_emit+0x3e4/0x600 kernel/printk/printk.c:2479
 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
 bio_check_eod block/blk-core.c:566 [inline]
 submit_bio_noacct+0x8c7/0x980 block/blk-core.c:806
 submit_bio+0x2a4/0x2c0 block/blk-core.c:926
 mpage_bio_submit_write fs/mpage.c:82 [inline]
 mpage_write_folio fs/mpage.c:593 [inline]
 __mpage_writepages+0x7fb/0x1390 fs/mpage.c:686
 mpage_writepages include/linux/mpage.h:27 [inline]
 fat_writepages+0x26/0x30 fs/fat/inode.c:200
 do_writepages+0x1c6/0x310 mm/page-writeback.c:2575
 __writeback_single_inode+0x7f/0x650 fs/fs-writeback.c:1764
 writeback_sb_inodes+0x4dd/0xaa0 fs/fs-writeback.c:2056
 wb_writeback+0x24e/0x560 fs/fs-writeback.c:2241
 wb_do_writeback fs/fs-writeback.c:2388 [inline]
 wb_workfn+0x194/0x930 fs/fs-writeback.c:2428
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0x4f0/0x9c0 kernel/workqueue.c:3385
 worker_thread+0x58a/0x780 kernel/workqueue.c:3466
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 22751 Comm: kworker/u8:18 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: writeback wb_workfn (flush-7:8)
==================================================================
kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=225, nr_sectors = 8 limit=128
kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=241, nr_sectors = 8 limit=128
kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=257, nr_sectors = 8 limit=128
kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=273, nr_sectors = 8 limit=128
kworker/u8:18: attempt to access beyond end of device
loop8: rw=1, sector=289, nr_sectors = 8 limit=128