loop3: detected capacity change from 0 to 764
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff88e5e550 of 8 bytes by task 15034 on cpu 0:
 data_alloc+0x203/0x2b0 kernel/printk/printk_ringbuffer.c:1082
 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
 set_capacity_and_notify+0x14c/0x1f0 block/genhd.c:93
 loop_set_size+0x2e/0x70 drivers/block/loop.c:210
 loop_configure+0x8d3/0xa50 drivers/block/loop.c:1068
 lo_ioctl+0x559/0x15d0 drivers/block/loop.c:-1
 blkdev_ioctl+0x34f/0x440 block/ioctl.c:704
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:893
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893
 x64_sys_call+0x19a8/0x2fb0 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 0xffffffff88e5e550 of 8 bytes by task 15030 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
 parse_rock_ridge_inode_internal+0xa0e/0x1030 fs/isofs/rock.c:377
 parse_rock_ridge_inode+0x3d/0xe0 fs/isofs/rock.c:677
 isofs_read_inode fs/isofs/inode.c:1408 [inline]
 __isofs_iget+0xbc4/0x1090 fs/isofs/inode.c:1512
 isofs_iget fs/isofs/isofs.h:135 [inline]
 isofs_fill_super+0xd66/0x1280 fs/isofs/inode.c:864
 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1681
 get_tree_bdev+0x1f/0x30 fs/super.c:1704
 isofs_get_tree+0x1c/0x30 fs/isofs/inode.c:1526
 vfs_get_tree+0x57/0x1d0 fs/super.c:1804
 do_new_mount+0x207/0x680 fs/namespace.c:3902
 path_mount+0x4a4/0xb20 fs/namespace.c:4226
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4427
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4427
 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: 0x00000000fffff6a5 -> 0x000000010000036a

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15030 Comm: syz.3.4383 Not tainted 6.16.0-rc5-syzkaller-00224-g379f604cc3dc #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
RRIP_1991A