BUG: KCSAN: data-race in desc_read_finalized_seq / prb_reserve

write to 0xffffffff868c3f78 of 8 bytes by task 32157 on cpu 1:
 prb_reserve+0x750/0xb80 kernel/printk/printk_ringbuffer.c:-1
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x174/0x6a0 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2457
 usb_gadget_register_driver_owner+0x179/0x1a0 drivers/usb/gadget/udc/core.c:1710
 raw_ioctl_run drivers/usb/gadget/legacy/raw_gadget.c:595 [inline]
 raw_ioctl+0xc8a/0x1f10 drivers/usb/gadget/legacy/raw_gadget.c:1306
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:892
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
 x64_sys_call+0x168d/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff868c3f78 of 8 bytes by task 32176 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 desc_read_finalized_seq+0x163/0x280 kernel/printk/printk_ringbuffer.c:1874
 prb_read kernel/printk/printk_ringbuffer.c:1922 [inline]
 _prb_read_valid+0x142/0x6c0 kernel/printk/printk_ringbuffer.c:2113
 desc_update_last_finalized kernel/printk/printk_ringbuffer.c:1515 [inline]
 prb_final_commit+0x147/0x200 kernel/printk/printk_ringbuffer.c:1782
 vprintk_store+0x737/0x860 kernel/printk/printk.c:2352
 vprintk_emit+0x174/0x6a0 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2457
 __ext4_error+0x225/0x320 fs/ext4/super.c:830
 ext4_xattr_inode_iget+0x7a/0x210 fs/ext4/xattr.c:435
 ext4_xattr_inode_get+0x95/0x250 fs/ext4/xattr.c:535
 ext4_xattr_move_to_block fs/ext4/xattr.c:2643 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2745 [inline]
 ext4_expand_extra_isize_ea+0x8b7/0x1000 fs/ext4/xattr.c:2837
 __ext4_expand_extra_isize+0x256/0x290 fs/ext4/inode.c:5893
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5936 [inline]
 __ext4_mark_inode_dirty+0x2cd/0x440 fs/ext4/inode.c:6014
 ext4_evict_inode+0x82d/0xdf0 fs/ext4/inode.c:256
 evict+0x2de/0x550 fs/inode.c:810
 iput_final fs/inode.c:1898 [inline]
 iput+0x42a/0x5b0 fs/inode.c:1924
 ext4_process_orphan+0x1a9/0x1c0 fs/ext4/orphan.c:360
 ext4_orphan_cleanup+0x69c/0x9f0 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5602 [inline]
 ext4_fill_super+0x330a/0x3650 fs/ext4/super.c:5722
 get_tree_bdev_flags+0x2b4/0x330 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5754
 vfs_get_tree+0x56/0x1e0 fs/super.c:1759
 do_new_mount+0x246/0x6b0 fs/namespace.c:3878
 path_mount+0x49b/0xb30 fs/namespace.c:4205
 do_mount fs/namespace.c:4218 [inline]
 __do_sys_mount fs/namespace.c:4429 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4406
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4406
 x64_sys_call+0xd11/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000002811 -> 0x0000000000004811

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 32176 Comm: syz.8.9112 Not tainted 6.14.0-syzkaller-03576-g1e1ba8d23dae #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
EXT4-fs (loop8): Remounting filesystem read-only
EXT4-fs warning (device loop8): ext4_evict_inode:259: couldn't mark inode dirty (err -5)
EXT4-fs (loop8): 1 orphan inode deleted
SELinux: (dev loop8, type ext4) getxattr errno 5