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

write to 0xffffffff868772d0 of 8 bytes by task 24648 on cpu 0:
 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
 br_set_state+0x28c/0x390 net/bridge/br_stp.c:57
 br_init_port+0x5c/0xf0 net/bridge/br_stp_if.c:39
 new_nbp+0x22b/0x300 net/bridge/br_if.c:442
 br_add_if+0x1e7/0xa60 net/bridge/br_if.c:599
 br_add_slave+0x2c/0x40 net/bridge/br_device.c:375
 do_set_master+0x38d/0x460 net/core/rtnetlink.c:2946
 rtnl_newlink_create+0x430/0x630 net/core/rtnetlink.c:3847
 __rtnl_newlink net/core/rtnetlink.c:3950 [inline]
 rtnl_newlink+0xf29/0x12d0 net/core/rtnetlink.c:4065
 rtnetlink_rcv_msg+0x5fb/0x6d0 net/core/rtnetlink.c:6955
 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6982
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x59e/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+0x142/0x180 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+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff868772d0 of 8 bytes by task 6532 on cpu 1:
 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_inode+0x30f/0x3f0 fs/ext4/super.c:843
 __check_block_validity fs/ext4/inode.c:395 [inline]
 ext4_map_blocks+0x9f4/0xd00 fs/ext4/inode.c:-1
 ext4_getblk+0x114/0x510 fs/ext4/inode.c:853
 ext4_bread+0x28/0x110 fs/ext4/inode.c:916
 ext4_quota_read+0xe8/0x260 fs/ext4/super.c:7253
 read_blk fs/quota/quota_tree.c:61 [inline]
 remove_tree+0x126/0x1120 fs/quota/quota_tree.c:555
 qtree_delete_dquot fs/quota/quota_tree.c:617 [inline]
 qtree_release_dquot+0x16e/0x180 fs/quota/quota_tree.c:787
 v2_release_dquot+0x98/0xd0 fs/quota/quota_v2.c:391
 dquot_release+0x10b/0x210 fs/quota/dquot.c:537
 ext4_release_dquot+0x1e4/0x460 fs/ext4/super.c:-1
 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:3319
 worker_thread+0x582/0x770 kernel/workqueue.c:3400
 kthread+0x486/0x510 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

value changed: 0xffffffffffff2478 -> 0x00000000000ad050

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 6532 Comm: kworker/u8:13 Not tainted 6.15.0-rc5-syzkaller-00275-gbec6f00f120e #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Workqueue: events_unbound quota_release_workfn
==================================================================
EXT4-fs error (device loop7): ext4_map_blocks:675: inode #3: block 1: comm kworker/u8:13: lblock 1 mapped to illegal pblock 1 (length 1)
EXT4-fs error (device loop7): ext4_release_dquot:6971: comm kworker/u8:13: Failed to release dquot type 0