EXT4-fs (loop6): Delayed block allocation failed for inode 15 at logical offset 3 with max blocks 1 with error 28
EXT4-fs (loop6): This should not happen!! Data will be lost
EXT4-fs (loop6): Total free blocks count 0
EXT4-fs (loop6): Free/Dirty block details
EXT4-fs (loop6): free_blocks=128
EXT4-fs (loop6): dirty_blocks=0
==================================================================
BUG: KCSAN: data-race in desc_read_finalized_seq / prb_reserve

write to 0xffffffff868dcea8 of 8 bytes by task 16492 on cpu 1:
 prb_reserve+0x750/0xb80 kernel/printk/printk_ringbuffer.c:-1
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 vhci_rx_pdu drivers/usb/usbip/vhci_rx.c:224 [inline]
 vhci_rx_loop+0x4d6/0x980 drivers/usb/usbip/vhci_rx.c:265
 kthread+0x4b7/0x540 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff868dcea8 of 8 bytes by task 16474 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 desc_read_finalized_seq+0x163/0x280 kernel/printk/printk_ringbuffer.c:1874
 prb_read kernel/printk/printk_ringbuffer.c:1922 [inline]
 _prb_read_valid+0x142/0x710 kernel/printk/printk_ringbuffer.c:2113
 prb_read_valid+0x42/0x70 kernel/printk/printk_ringbuffer.c:2185
 __console_flush_and_unlock kernel/printk/printk.c:3304 [inline]
 console_unlock+0x1be/0x350 kernel/printk/printk.c:3325
 vprintk_emit+0x470/0x6c0 kernel/printk/printk.c:2450
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 __ext4_msg+0x198/0x1b0 fs/ext4/super.c:985
 ext4_print_free_blocks+0x13c/0x190 fs/ext4/inode.c:1636
 mpage_map_and_submit_extent fs/ext4/inode.c:2304 [inline]
 ext4_do_writepages+0x1a7f/0x21d0 fs/ext4/inode.c:2738
 ext4_writepages+0x183/0x320 fs/ext4/inode.c:2828
 do_writepages+0x1d8/0x480 mm/page-writeback.c:2656
 filemap_fdatawrite_wbc mm/filemap.c:386 [inline]
 __filemap_fdatawrite_range mm/filemap.c:419 [inline]
 file_write_and_wait_range+0x16e/0x2f0 mm/filemap.c:794
 generic_buffers_fsync_noflush+0x46/0x120 fs/buffer.c:600
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1c3/0x6c0 fs/ext4/fsync.c:147
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2976 [inline]
 ext4_buffered_write_iter+0x358/0x3c0 fs/ext4/file.c:305
 ext4_file_write_iter+0x3b2/0xf80 include/linux/fs.h:-1
 do_iter_readv_writev+0x40d/0x4b0 fs/read_write.c:-1
 vfs_writev+0x2da/0x880 fs/read_write.c:1055
 do_pwritev fs/read_write.c:1151 [inline]
 __do_sys_pwritev2 fs/read_write.c:1209 [inline]
 __se_sys_pwritev2+0x103/0x1d0 fs/read_write.c:1200
 __x64_sys_pwritev2+0x78/0x90 fs/read_write.c:1200
 x64_sys_call+0x1c86/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:329
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000002c3b -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16474 Comm: syz.6.4021 Not tainted 6.15.0-rc1-syzkaller-00288-ge618ee89561b #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
EXT4-fs (loop6): Block reservation details
EXT4-fs (loop6): i_reserved_data_blocks=0