EXT4-fs error (device loop3): ext4_mb_generate_buddy:1220: group 0, block bitmap and bg descriptor inconsistent: 0 vs 150994969 free clusters
EXT4-fs (loop3): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 2048 with error 28
EXT4-fs (loop3): This should not happen!! Data will be lost
EXT4-fs (loop3): Total free blocks count 0
EXT4-fs (loop3): Free/Dirty block details
==================================================================
BUG: KCSAN: data-race in console_flush_all / console_flush_all

write to 0xffffffff86a21238 of 8 bytes by task 10791 on cpu 1:
 console_emit_next_record kernel/printk/printk.c:3099 [inline]
 console_flush_all+0x35a/0x730 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xa1/0x330 kernel/printk/printk.c:3325
 vprintk_emit+0x388/0x650 kernel/printk/printk.c:2450
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 chnl_net_open+0x2a9/0x560 net/caif/chnl_net.c:260
 __dev_open+0x2d5/0x530 net/core/dev.c:1683
 __dev_change_flags+0x163/0x400 net/core/dev.c:9458
 netif_change_flags+0x5a/0xd0 net/core/dev.c:9521
 do_setlink+0x9d2/0x2810 net/core/rtnetlink.c:3141
 rtnl_group_changelink net/core/rtnetlink.c:3773 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3927 [inline]
 rtnl_newlink+0xd8b/0x12d0 net/core/rtnetlink.c:4055
 rtnetlink_rcv_msg+0x5fe/0x6d0 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6971
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x5a1/0x670 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x145/0x180 net/socket.c:727
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655
 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86a21238 of 8 bytes by task 9488 on cpu 0:
 console_flush_all+0x563/0x730 kernel/printk/printk.c:3227
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xa1/0x330 kernel/printk/printk.c:3325
 vprintk_emit+0x388/0x650 kernel/printk/printk.c:2450
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 __ext4_msg+0x18f/0x1a0 fs/ext4/super.c:981
 ext4_print_free_blocks fs/ext4/inode.c:1751 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2429 [inline]
 ext4_do_writepages+0x19a4/0x21c0 fs/ext4/inode.c:2863
 ext4_writepages+0x176/0x300 fs/ext4/inode.c:2953
 do_writepages+0x1c3/0x310 mm/page-writeback.c:2636
 __writeback_single_inode+0x80/0x7c0 fs/fs-writeback.c:1680
 writeback_sb_inodes+0x480/0xa20 fs/fs-writeback.c:1976
 __writeback_inodes_wb+0x94/0x1a0 fs/fs-writeback.c:2047
 wb_writeback+0x266/0x5c0 fs/fs-writeback.c:2158
 wb_check_start_all fs/fs-writeback.c:2284 [inline]
 wb_do_writeback fs/fs-writeback.c:2310 [inline]
 wb_workfn+0x4c9/0x910 fs/fs-writeback.c:2343
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x489/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000001cef -> 0x0000000000001cf0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 9488 Comm: kworker/u8:37 Not tainted 6.16.0-rc4-syzkaller-00308-ga79a588fc176 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: writeback wb_workfn (flush-7:3)
==================================================================
EXT4-fs (loop3): free_blocks=2415919504
EXT4-fs (loop3): dirty_blocks=6880
EXT4-fs (loop3): Block reservation details
EXT4-fs (loop3): i_reserved_data_blocks=430
EXT4-fs (loop3): Delayed block allocation failed for inode 18 at logical offset 2048 with max blocks 2048 with error 28
EXT4-fs (loop3): This should not happen!! Data will be lost