EXT4-fs error (device loop9): __ext4_ext_dirty:207: inode #13: comm syz.9.20476: mark_inode_dirty error
EXT4-fs error (device loop9): ext4_do_update_inode:5211: inode #13: comm syz.9.20476: corrupted inode contents
==================================================================
BUG: KCSAN: data-race in desc_read_finalized_seq / prb_reserve

write to 0xffffffff868e4090 of 8 bytes by task 576 on cpu 1:
 prb_reserve+0x750/0xb80 kernel/printk/printk_ringbuffer.c:-1
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 _fat_msg+0xa4/0xd0 fs/fat/misc.c:62
 fat__get_entry fs/fat/dir.c:102 [inline]
 fat_get_entry+0x546/0x5f0 fs/fat/dir.c:128
 fat_get_short_entry fs/fat/dir.c:885 [inline]
 fat_subdirs+0xfc/0x1a0 fs/fat/dir.c:951
 fat_read_root+0x317/0x360 fs/fat/inode.c:1345
 fat_fill_super+0x1548/0x1c70 fs/fat/inode.c:1814
 vfat_fill_super+0x24/0x30 fs/fat/namei_vfat.c:1197
 get_tree_bdev_flags+0x2b4/0x330 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 vfat_get_tree+0x1c/0x30 fs/fat/namei_vfat.c:1202
 vfs_get_tree+0x56/0x1e0 fs/super.c:1759
 do_new_mount+0x246/0x6b0 fs/namespace.c:3881
 path_mount+0x49b/0xb30 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4409
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4409
 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+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff868e4090 of 8 bytes by task 578 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+0x142/0x710 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+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 __ext4_error_inode+0x2e7/0x410 fs/ext4/super.c:848
 ext4_do_update_inode fs/ext4/inode.c:5211 [inline]
 ext4_mark_iloc_dirty+0x383/0xdb0 fs/ext4/inode.c:5869
 ext4_orphan_del+0x6f2/0x720 fs/ext4/orphan.c:303
 ext4_truncate+0x8c2/0xb30 fs/ext4/inode.c:4252
 ext4_process_orphan+0x113/0x1c0 fs/ext4/orphan.c:339
 ext4_orphan_cleanup+0x69c/0x9f0 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5607 [inline]
 ext4_fill_super+0x3215/0x3580 fs/ext4/super.c:5726
 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:5758
 vfs_get_tree+0x56/0x1e0 fs/super.c:1759
 do_new_mount+0x246/0x6b0 fs/namespace.c:3881
 path_mount+0x49b/0xb30 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4409
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4409
 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+0xc9/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000008de4 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 578 Comm: syz.9.20476 Tainted: G        W           6.15.0-rc3-syzkaller-00032-ga79be02bba5c #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
EXT4-fs error (device loop9) in ext4_orphan_del:305: Corrupt filesystem
EXT4-fs error (device loop9): ext4_do_update_inode:5211: inode #13: comm syz.9.20476: corrupted inode contents
EXT4-fs error (device loop9): ext4_truncate:4255: inode #13: comm syz.9.20476: mark_inode_dirty error
EXT4-fs error (device loop9) in ext4_process_orphan:347: Corrupt filesystem
EXT4-fs (loop9): 1 truncate cleaned up
EXT4-fs (loop9): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
EXT4-fs error (device loop9): ext4_acquire_dquot:6935: comm syz.9.20476: Failed to acquire dquot type 0
EXT4-fs (loop9): re-mounted 00000000-0000-0000-0000-000000000000 ro.