EXT4-fs error (device loop6): ext4_map_blocks:783: inode #3: block 1: comm kworker/u8:33: lblock 1 mapped to illegal pblock 1 (length 1)
==================================================================
BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff86882f00 of 8 bytes by task 29468 on cpu 0:
 data_alloc+0x31c/0x390 kernel/printk/printk_ringbuffer.c:1130
 prb_reserve+0x8d7/0xad0 kernel/printk/printk_ringbuffer.c:1724
 vprintk_store+0x53c/0x830 kernel/printk/printk.c:2302
 vprintk_emit+0x15a/0x5c0 kernel/printk/printk.c:2402
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2451
 __ext4_error_inode+0x30f/0x3f0 fs/ext4/super.c:848
 __check_block_validity fs/ext4/inode.c:389 [inline]
 ext4_map_blocks+0xa66/0xd20 fs/ext4/inode.c:-1
 ext4_getblk+0x114/0x510 fs/ext4/inode.c:984
 ext4_bread+0x28/0x110 fs/ext4/inode.c:1047
 ext4_quota_read+0xe8/0x260 fs/ext4/super.c:7304
 read_blk fs/quota/quota_tree.c:61 [inline]
 find_next_id+0x220/0x540 fs/quota/quota_tree.c:808
 qtree_get_next_id+0x55/0x120 fs/quota/quota_tree.c:847
 v2_get_next_id+0x81/0xc0 fs/quota/quota_v2.c:412
 dquot_get_next_id+0xb2/0xe0 fs/quota/dquot.c:2193
 dquot_get_next_dqblk+0x44/0x200 fs/quota/dquot.c:2705
 quota_getnextquota+0x16e/0x2c0 fs/quota/quota.c:250
 do_quotactl+0x38f/0x670 fs/quota/quota.c:800
 __do_sys_quotactl fs/quota/quota.c:961 [inline]
 __se_sys_quotactl+0x3a5/0x670 fs/quota/quota.c:917
 __x64_sys_quotactl+0x55/0x70 fs/quota/quota.c:917
 x64_sys_call+0x19a4/0x3000 arch/x86/include/generated/asm/syscalls_64.h:180
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86882f00 of 8 bytes by task 6578 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:496 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:792 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:938 [inline]
 prb_reserve+0x207/0xad0 kernel/printk/printk_ringbuffer.c:1674
 vprintk_store+0x53c/0x830 kernel/printk/printk.c:2302
 vprintk_emit+0x15a/0x5c0 kernel/printk/printk.c:2402
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2441
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2451
 __ext4_error+0x248/0x320 fs/ext4/super.c:822
 ext4_release_dquot+0x2e7/0x460 fs/ext4/super.c:7020
 quota_release_workfn+0x256/0x530 fs/quota/dquot.c:843
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0x4ce/0x9d0 kernel/workqueue.c:3340
 worker_thread+0x582/0x770 kernel/workqueue.c:3421
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x149/0x290 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

value changed: 0x00000000000b31b8 -> 0x0000000000146038

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6578 Comm: kworker/u8:33 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: quota_events_unbound quota_release_workfn
==================================================================
EXT4-fs error (device loop6): ext4_release_dquot:7022: comm kworker/u8:33: Failed to release dquot type 0
bond0 (unregistering): Released all slaves
tipc: Left network mode
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
pimreg3 (unregistering): left allmulticast mode