loop4: detected capacity change from 0 to 2048
EXT4-fs mount: 32 callbacks suppressed
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff8861ed5d of 1 bytes by task 1504 on cpu 1:
 vsnprintf+0xdd8/0xe30
 va_format lib/vsprintf.c:1683 [inline]
 pointer+0x8a1/0xd20 lib/vsprintf.c:2455
 vsnprintf+0x861/0xe30 lib/vsprintf.c:2828
 vscnprintf+0x42/0x90 lib/vsprintf.c:2930
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2165
 vprintk_store+0x570/0x810 kernel/printk/printk.c:2279
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 __netdev_printk+0x2d1/0x3e0 net/core/dev.c:11761
 netdev_info+0x99/0xc0 net/core/dev.c:11808
 bond_uninit+0x1ed/0x320 drivers/net/bonding/bond_main.c:5935
 unregister_netdevice_many_notify+0xc1c/0x1110 net/core/dev.c:11365
 unregister_netdevice_many+0x19/0x20 net/core/dev.c:11405
 cleanup_net+0x417/0x830 net/core/net_namespace.c:635
 process_one_work kernel/workqueue.c:3231 [inline]
 process_scheduled_works+0x483/0x9a0 kernel/workqueue.c:3312
 worker_thread+0x526/0x700 kernel/workqueue.c:3390
 kthread+0x1d1/0x210 kernel/kthread.c:389
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read to 0xffffffff8861ed58 of 8 bytes by task 11061 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2269
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:990
 ext4_fill_super+0x980/0x39e0 fs/ext4/super.c:5679
 get_tree_bdev+0x256/0x2e0 fs/super.c:1624
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5696
 vfs_get_tree+0x56/0x1d0 fs/super.c:1789
 do_new_mount+0x227/0x690 fs/namespace.c:3472
 path_mount+0x49b/0xb30 fs/namespace.c:3799
 do_mount fs/namespace.c:3812 [inline]
 __do_sys_mount fs/namespace.c:4020 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:3997
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3997
 x64_sys_call+0xd11/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000fffff439 -> 0x0000000a73657661

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11061 Comm: syz.4.2008 Not tainted 6.10.0-syzkaller-10729-g3c3ff7be9729 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================
EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.