loop0: detected capacity change from 0 to 512
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff870ed7e8 of 8 bytes by task 2038 on cpu 0:
 data_alloc+0x216/0x2c0 kernel/printk/printk_ringbuffer.c:1074
 prb_reserve+0x897/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 __show_regs+0xd7/0x430 arch/x86/kernel/process_64.c:88
 show_trace_log_lvl+0x3d2/0x510 arch/x86/kernel/dumpstack.c:301
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xda/0x130 lib/dump_stack.c:106
 dump_stack+0x15/0x20 lib/dump_stack.c:113
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail_ex+0x21f/0x230 lib/fault-inject.c:153
 __should_fail_alloc_page+0xfd/0x110 mm/fail_page_alloc.c:42
 prepare_alloc_pages mm/page_alloc.c:4342 [inline]
 __alloc_pages+0x108/0x340 mm/page_alloc.c:4558
 alloc_pages_mpol+0xb1/0x1d0 mm/mempolicy.c:2133
 alloc_pages+0xe0/0x100 mm/mempolicy.c:2204
 pagetable_alloc include/linux/mm.h:2842 [inline]
 __pte_alloc_one include/asm-generic/pgalloc.h:68 [inline]
 pte_alloc_one+0x32/0xe0 arch/x86/mm/pgtable.c:33
 __pte_alloc+0x33/0x270 mm/memory.c:440
 copy_pte_range mm/memory.c:1048 [inline]
 copy_pmd_range mm/memory.c:1187 [inline]
 copy_pud_range mm/memory.c:1224 [inline]
 copy_p4d_range mm/memory.c:1248 [inline]
 copy_page_range+0x1c5f/0x2150 mm/memory.c:1346
 dup_mmap kernel/fork.c:745 [inline]
 dup_mm kernel/fork.c:1685 [inline]
 copy_mm+0x93a/0x1070 kernel/fork.c:1734
 copy_process+0x1002/0x20a0 kernel/fork.c:2497
 kernel_clone+0x169/0x560 kernel/fork.c:2902
 __do_sys_clone3 kernel/fork.c:3203 [inline]
 __se_sys_clone3+0x1b5/0x1f0 kernel/fork.c:3187
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3187
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff870ed7e8 of 8 bytes by task 2044 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x897/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 set_capacity_and_notify+0x11d/0x170 block/genhd.c:86
 loop_set_size+0x2e/0x70 drivers/block/loop.c:235
 loop_configure+0xaf9/0xca0 drivers/block/loop.c:1096
 lo_ioctl+0x682/0x12e0
 blkdev_ioctl+0x375/0x460 block/ioctl.c:634
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xcf/0x140 fs/ioctl.c:857
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000100002b4d -> 0x0000000100003a85

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2044 Comm: syz-executor.0 Not tainted 6.8.0-rc7-syzkaller-00142-g3aaa8ce7a335 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
ext4: Unknown parameter 'ÿÿÿÿ'
net_ratelimit: 1 callbacks suppressed
A link change request failed with some changes committed already. Interface caif0 may have been left with an inconsistent configuration, please check.