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

write to 0xffffffff8693a0f8 of 88 bytes by task 17172 on cpu 0:
 prb_reserve+0x696/0xaf0 kernel/printk/printk_ringbuffer.c:1635
 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_msg+0x18f/0x1a0 fs/ext4/super.c:981
 ext4_setup_super+0x1db/0x580 fs/ext4/super.c:-1
 __ext4_fill_super fs/ext4/super.c:5522 [inline]
 ext4_fill_super+0x27d4/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1679
 get_tree_bdev+0x1f/0x30 fs/super.c:1702
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x57/0x1d0 fs/super.c:1802
 do_new_mount+0x207/0x680 fs/namespace.c:3856
 path_mount+0x4a4/0xb20 fs/namespace.c:4180
 do_mount fs/namespace.c:4193 [inline]
 __do_sys_mount fs/namespace.c:4404 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4381
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4381
 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 0xffffffff8693a0f8 of 8 bytes by task 17159 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x383/0x920 kernel/printk/printk_ringbuffer.c:2114
 desc_update_last_finalized kernel/printk/printk_ringbuffer.c:1515 [inline]
 prb_final_commit+0x136/0x1e0 kernel/printk/printk_ringbuffer.c:1782
 vprintk_store+0x741/0x860 kernel/printk/printk.c:2352
 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_orphan_get+0x326/0x430 fs/ext4/ialloc.c:1421
 ext4_orphan_cleanup+0x5fa/0xa00 fs/ext4/orphan.c:467
 __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:1679
 get_tree_bdev+0x1f/0x30 fs/super.c:1702
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x57/0x1d0 fs/super.c:1802
 do_new_mount+0x207/0x680 fs/namespace.c:3856
 path_mount+0x4a4/0xb20 fs/namespace.c:4180
 do_mount fs/namespace.c:4193 [inline]
 __do_sys_mount fs/namespace.c:4404 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4381
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4381
 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

value changed: 0x0000000000003d39 -> 0x0000000000005d39

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17159 Comm: syz.9.24080 Not tainted 6.15.0-syzkaller-13743-g8630c59e9936 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
is_bad_inode(inode)=0
NEXT_ORPHAN(inode)=2147418128
max_ino=32
i_nlink=0