BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff88e2b208 of 1 bytes by task 7634 on cpu 0:
 vsnprintf+0x2ce/0x890 lib/vsprintf.c:2826
 vscnprintf+0x41/0x90 lib/vsprintf.c:2939
 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
 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline]
 show_trace_log_lvl+0x4e3/0x560 arch/x86/kernel/dumpstack.c:282
 __dump_stack+0x1d/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0xe8/0x140 lib/dump_stack.c:120
 dump_stack+0x15/0x1b lib/dump_stack.c:129
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x265/0x280 lib/fault-inject.c:174
 should_failslab+0x8c/0xb0 mm/failslab.c:46
 slab_pre_alloc_hook mm/slub.c:4101 [inline]
 slab_alloc_node mm/slub.c:4177 [inline]
 __kmalloc_cache_noprof+0x4c/0x320 mm/slub.c:4354
 kmalloc_noprof include/linux/slab.h:905 [inline]
 tipc_topsrv_queue_evt+0x1c3/0x300 net/tipc/topsrv.c:328
 tipc_sub_send_event net/tipc/subscr.c:63 [inline]
 tipc_sub_report_overlap+0x2ef/0x310 net/tipc/subscr.c:102
 tipc_service_insert_publ net/tipc/name_table.c:366 [inline]
 tipc_nametbl_insert_publ+0x86c/0x930 net/tipc/name_table.c:491
 tipc_nametbl_publish+0x112/0x1c0 net/tipc/name_table.c:776
 tipc_sk_publish+0x121/0x200 net/tipc/socket.c:2915
 tipc_sk_join+0x24b/0x2e0 net/tipc/socket.c:3093
 tipc_setsockopt+0x598/0x620 net/tipc/socket.c:3200
 do_sock_setsockopt net/socket.c:2296 [inline]
 __sys_setsockopt+0x184/0x200 net/socket.c:2321
 __do_sys_setsockopt net/socket.c:2327 [inline]
 __se_sys_setsockopt net/socket.c:2324 [inline]
 __x64_sys_setsockopt+0x64/0x80 net/socket.c:2324
 x64_sys_call+0x2bd5/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:55
 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 0xffffffff88e2b208 of 8 bytes by task 7624 on cpu 1:
 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_std_error+0x346/0x370 fs/ext4/super.c:956
 ext4_mb_clear_bb fs/ext4/mballoc.c:6548 [inline]
 ext4_free_blocks+0x12e7/0x1400 fs/ext4/mballoc.c:6651
 ext4_clear_blocks+0x2a2/0x2c0 fs/ext4/indirect.c:888
 ext4_free_data fs/ext4/indirect.c:962 [inline]
 ext4_ind_truncate+0x599/0x830 fs/ext4/indirect.c:1154
 ext4_truncate+0x6d7/0xad0 fs/ext4/inode.c:4576
 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:5605 [inline]
 ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x291/0x300 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+0x54/0x1d0 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: 0x00000000ffffeeb4 -> 0x6f745f6370697420

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7624 Comm: syz.1.1420 Not tainted 6.15.0-syzkaller-11802-g1af80d00e1e0 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
EXT4-fs error (device loop1): ext4_free_branches:1023: inode #11: comm syz.1.1420: invalid indirect mapped block 3 (level 2)
EXT4-fs (loop1): 2 truncates cleaned up
EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.