syzbot

EXT4-fs warning (device loop5): ext4_update_dynamic_rev:1132: updating to rev 1 because of new feature flag, running e2fsck is recommended
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e43850 of 1 bytes by task 29 on cpu 1:
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x187/0x220 lib/vsprintf.c:721
 vsnprintf+0x532/0x890 lib/vsprintf.c:2852
 vscnprintf+0x41/0x90 lib/vsprintf.c:2917
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 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+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

read to 0xffffffff88e43850 of 8 bytes by task 32061 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 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
 __ext4_warning+0x12b/0x140 fs/ext4/super.c:1010
 ext4_update_dynamic_rev+0x7c/0xc0 fs/ext4/super.c:1129
 ext4_set_feature_large_file fs/ext4/ext4.h:2127 [inline]
 ext4_do_update_inode fs/ext4/inode.c:5232 [inline]
 ext4_mark_iloc_dirty+0xb49/0xda0 fs/ext4/inode.c:5869
 __ext4_mark_inode_dirty+0x2e2/0x3f0 fs/ext4/inode.c:6074
 ext4_ext_truncate+0x5a/0x170 fs/ext4/extents.c:4457
 ext4_truncate+0x6f8/0xac0 fs/ext4/inode.c:4232
 ext4_process_orphan+0x110/0x1c0 fs/ext4/orphan.c:339
 ext4_orphan_cleanup+0x6a8/0xa00 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5607 [inline]
 ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5726
 get_tree_bdev_flags+0x28e/0x300 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+0x54/0x1d0 fs/super.c:1759
 do_new_mount+0x207/0x680 fs/namespace.c:3884
 path_mount+0x4a4/0xb20 fs/namespace.c:4211
 do_mount fs/namespace.c:4224 [inline]
 __do_sys_mount fs/namespace.c:4435 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4412
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4412
 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+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000100001064 -> 0x7974696c69626170

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 32061 Comm: syz.5.10632 Not tainted 6.15.0-rc4-syzkaller-00296-ge8ab83e34bdc #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
==================================================================
EXT4-fs (loop5): 1 truncate cleaned up
EXT4-fs (loop5): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.