loop1: detected capacity change from 0 to 1
 loop1: p1 p2 p3
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff870adc82 of 1 bytes by task 12412 on cpu 1:
 string_nocheck lib/vsprintf.c:647 [inline]
 string+0x17b/0x220 lib/vsprintf.c:725
 vsnprintf+0xb57/0xe80 lib/vsprintf.c:2800
 vscnprintf+0x3e/0x80 lib/vsprintf.c:2906
 printk_sprint kernel/printk/printk.c:2089 [inline]
 vprintk_store+0x5f2/0xb50 kernel/printk/printk.c:2203
 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2249
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2279
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x96 kernel/printk/printk.c:2289
 check_partition block/partitions/core.c:158 [inline]
 blk_add_partitions block/partitions/core.c:602 [inline]
 bdev_disk_changed+0x9eb/0xbf0 block/partitions/core.c:688
 loop_reread_partitions drivers/block/loop.c:518 [inline]
 loop_set_status+0x496/0x530 drivers/block/loop.c:1322
 lo_ioctl+0x83e/0x1290
 blkdev_ioctl+0x20e/0x440 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff870adc80 of 8 bytes by task 12414 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x10f/0x440 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x897/0xbd0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x51c/0xb50 kernel/printk/printk.c:2193
 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2249
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2279
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x96 kernel/printk/printk.c:2289
 check_partition block/partitions/core.c:158 [inline]
 blk_add_partitions block/partitions/core.c:602 [inline]
 bdev_disk_changed+0x9eb/0xbf0 block/partitions/core.c:688
 loop_reread_partitions drivers/block/loop.c:518 [inline]
 loop_set_status+0x496/0x530 drivers/block/loop.c:1322
 lo_ioctl+0x83e/0x1290
 blkdev_ioctl+0x20e/0x440 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000100002963 -> 0x203a35706f6f6c20

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12414 Comm: syz-executor.1 Not tainted 6.1.0-rc1-syzkaller-00427-gd47136c28015-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
==================================================================
loop1: p1 start 10 is beyond EOD, truncated
loop1: p2 start 14414015 is beyond EOD, truncated
loop1: p3 size 1073741824 extends beyond EOD, truncated