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

write to 0xffffffff8688d388 of 8 bytes by task 19506 on cpu 1:
 data_alloc+0x27d/0x2b0 kernel/printk/printk_ringbuffer.c:1096
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 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_std_error+0x346/0x370 fs/ext4/super.c:956
 ext4_free_inode+0x79e/0x870 fs/ext4/ialloc.c:361
 ext4_evict_inode+0xaff/0xd80 fs/ext4/inode.c:306
 evict+0x2e0/0x550 fs/inode.c:810
 iput_final fs/inode.c:1898 [inline]
 iput+0x447/0x5b0 fs/inode.c:1924
 ext4_process_orphan+0x1a9/0x1c0 fs/ext4/orphan.c:360
 ext4_orphan_cleanup+0x6a8/0xa00 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5605 [inline]
 ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1681
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x57/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 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 0xffffffff8688d388 of 8 bytes by task 17553 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline]
 prb_reserve+0x221/0xaf0 kernel/printk/printk_ringbuffer.c:1619
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 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_error+0x248/0x320 fs/ext4/super.c:813
 ext4_release_dquot+0x2e7/0x460 fs/ext4/super.c:6967
 quota_release_workfn+0x253/0x530 fs/quota/dquot.c:840
 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: 0x0000000000038e28 -> 0x00000000000e6440

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 17553 Comm: kworker/u8:26 Not tainted 6.16.0-rc6-syzkaller-00037-ge2291551827f #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound quota_release_workfn
==================================================================
EXT4-fs error (device loop8): ext4_release_dquot:6969: comm kworker/u8:26: Failed to release dquot type 0
EXT4-fs error (device loop8): ext4_release_dquot:6969: comm kworker/u8:26: Failed to release dquot type 0