==================================================================
BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff86c71a08 of 8 bytes by task 14533 on cpu 0:
 data_alloc+0x31c/0x390 kernel/printk/printk_ringbuffer.c:1130
 prb_reserve+0x8d7/0xae0 kernel/printk/printk_ringbuffer.c:1724
 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
 __ext4_error+0x225/0x310 fs/ext4/super.c:823
 __ext4_get_inode_loc+0x374/0x930 fs/ext4/inode.c:4781
 ext4_get_inode_loc fs/ext4/inode.c:4915 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6235
 ext4_xattr_set_handle+0x3a1/0xf80 fs/ext4/xattr.c:2397
 __ext4_set_acl+0x313/0x380 fs/ext4/acl.c:217
 ext4_set_acl+0x2b8/0x3e0 fs/ext4/acl.c:259
 set_posix_acl fs/posix_acl.c:955 [inline]
 vfs_set_acl+0x615/0x7d0 fs/posix_acl.c:1134
 do_set_acl+0x96/0x130 fs/posix_acl.c:1279
 do_setxattr fs/xattr.c:633 [inline]
 filename_setxattr+0x212/0x410 fs/xattr.c:664
 path_setxattrat+0x2be/0x310 fs/xattr.c:708
 __do_sys_setxattr fs/xattr.c:742 [inline]
 __se_sys_setxattr fs/xattr.c:738 [inline]
 __x64_sys_setxattr+0x6e/0x90 fs/xattr.c:738
 x64_sys_call+0x2ee2/0x3020 arch/x86/include/generated/asm/syscalls_64.h:189
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86c71a08 of 8 bytes by task 12437 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+0x207/0xae0 kernel/printk/printk_ringbuffer.c:1674
 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
 __ext4_error+0x225/0x310 fs/ext4/super.c:823
 ext4_release_dquot+0x2e6/0x460 fs/ext4/super.c:7037
 quota_release_workfn+0x260/0x540 fs/quota/dquot.c:843
 process_one_work kernel/workqueue.c:3275 [inline]
 process_scheduled_works+0x4de/0x9e0 kernel/workqueue.c:3358
 worker_thread+0x581/0x770 kernel/workqueue.c:3439
 kthread+0x22a/0x280 kernel/kthread.c:467
 ret_from_fork+0x150/0x360 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0xfffffffffffd4f90 -> 0x000000000006fae0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12437 Comm: kworker/u8:31 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: quota_events_unbound quota_release_workfn
==================================================================
EXT4-fs error (device loop2): ext4_release_dquot:7039: comm kworker/u8:31: Failed to release dquot type 0
loop2: lost filesystem error report for type 5 error -117