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

write to 0xffffffff86888868 of 8 bytes by task 29 on cpu 1:
 data_alloc+0x271/0x2b0 kernel/printk/printk_ringbuffer.c:1095
 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
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1b1/0x1c0 kernel/audit.c:581
 kauditd_send_queue+0x270/0x2c0 kernel/audit.c:766
 kauditd_thread+0x421/0x630 kernel/audit.c:890
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff86888868 of 16 bytes by task 23598 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1874 [inline]
 prb_read kernel/printk/printk_ringbuffer.c:1922 [inline]
 _prb_read_valid+0x1bc/0x920 kernel/printk/printk_ringbuffer.c:2113
 desc_update_last_finalized kernel/printk/printk_ringbuffer.c:1515 [inline]
 prb_final_commit+0x136/0x1e0 kernel/printk/printk_ringbuffer.c:1782
 vprintk_store+0x7c4/0x860 kernel/printk/printk.c:2310
 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_grp_locked_error+0x5d0/0x7b0 fs/ext4/super.c:1054
 ext4_mb_generate_buddy+0x240/0x2c0 fs/ext4/mballoc.c:1286
 ext4_mb_init_cache+0x847/0xba0 fs/ext4/mballoc.c:1475
 ext4_mb_init_group+0x25b/0x3f0 fs/ext4/mballoc.c:1612
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2797 [inline]
 ext4_mb_scan_group+0x5f4/0xf10 fs/ext4/mballoc.c:2934
 ext4_mb_scan_groups_linear fs/ext4/mballoc.c:1146 [inline]
 ext4_mb_scan_groups fs/ext4/mballoc.c:1180 [inline]
 ext4_mb_regular_allocator+0x70a/0x15e0 fs/ext4/mballoc.c:3026
 ext4_mb_new_blocks+0x800/0x2080 fs/ext4/mballoc.c:6285
 ext4_new_meta_blocks+0xc3/0x1b0 fs/ext4/balloc.c:750
 ext4_xattr_block_set+0x10ff/0x1a30 fs/ext4/xattr.c:2113
 ext4_xattr_move_to_block fs/ext4/xattr.c:2659 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2734 [inline]
 ext4_expand_extra_isize_ea+0xc65/0x11f0 fs/ext4/xattr.c:2822
 __ext4_expand_extra_isize+0x246/0x280 fs/ext4/inode.c:6385
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:6428 [inline]
 __ext4_mark_inode_dirty+0x29d/0x3f0 fs/ext4/inode.c:6506
 ext4_evict_inode+0x80e/0xd90 fs/ext4/inode.c:254
 evict+0x2e0/0x550 fs/inode.c:810
 iput_final fs/inode.c:1897 [inline]
 iput+0x447/0x5b0 fs/inode.c:1923
 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:5609 [inline]
 ext4_fill_super+0x3260/0x35d0 fs/ext4/super.c:5728
 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1692
 get_tree_bdev+0x1f/0x30 fs/super.c:1715
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5760
 vfs_get_tree+0x57/0x1d0 fs/super.c:1815
 do_new_mount+0x207/0x5e0 fs/namespace.c:3808
 path_mount+0x4a4/0xb20 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4324
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4324
 x64_sys_call+0x2b4d/0x2ff0 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 23598 Comm: syz.4.7457 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================
EXT4-fs error (device loop4): ext4_xattr_inode_iget:433: comm syz.4.7457: Parent and EA inode have the same ino 15
EXT4-fs (loop4): 1 orphan inode deleted
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
syz.4.7457 (23598) used greatest stack depth: 8200 bytes left