) failed (rc=-5)
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff88e8baa0 of 8 bytes by task 27363 on cpu 0:
 data_alloc+0x1d5/0x2e0 kernel/printk/printk_ringbuffer.c:1088
 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299
 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2448
 blk_add_partition block/partitions/core.c:549 [inline]
 blk_add_partitions block/partitions/core.c:633 [inline]
 bdev_disk_changed+0x874/0xcb0 block/partitions/core.c:693
 loop_reread_partitions drivers/block/loop.c:449 [inline]
 loop_set_status+0x5d2/0x6a0 drivers/block/loop.c:1278
 loop_set_status64 drivers/block/loop.c:1374 [inline]
 lo_ioctl+0x671/0x12b0 drivers/block/loop.c:1560
 blkdev_ioctl+0x356/0x440 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1816/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
 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 0xffffffff88e8baa0 of 8 bytes by task 27392 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:591 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:676
 data_alloc+0xfb/0x2e0 kernel/printk/printk_ringbuffer.c:1061
 prb_reserve+0x807/0xaf0 kernel/printk/printk_ringbuffer.c:1685
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299
 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2448
 loop_reread_partitions+0xab/0xb0 drivers/block/loop.c:452
 loop_configure+0x981/0x9c0 drivers/block/loop.c:1098
 lo_ioctl+0x5aa/0x12b0 drivers/block/loop.c:1544
 blkdev_ioctl+0x356/0x440 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
 x64_sys_call+0x1816/0x3000 arch/x86/include/generated/asm/syscalls_64.h:17
 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: 0x00000000ffffecc8 -> 0x00000000fffff8ae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 27392 Comm: syz.1.2695 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
==================================================================
xt_recent: Unsupported userspace flags (000000b1)