loop3: detected capacity change from 0 to 512 ================================================================== BUG: KCSAN: data-race in _prb_read_valid / prb_reserve_in_last write to 0xffffffff86e7cde8 of 8 bytes by task 2981 on cpu 1: data_realloc kernel/printk/printk_ringbuffer.c:1228 [inline] prb_reserve_in_last+0x9c7/0xae0 kernel/printk/printk_ringbuffer.c:1498 vprintk_store+0x45b/0x910 kernel/printk/printk.c:2328 vprintk_emit+0x1a4/0x610 kernel/printk/printk.c:2455 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 disk_unlock_native_capacity block/partitions/core.c:522 [inline] blk_add_partition block/partitions/core.c:545 [inline] blk_add_partitions block/partitions/core.c:635 [inline] bdev_disk_changed+0xacb/0xe20 block/partitions/core.c:695 blkdev_get_whole+0x1e8/0x2c0 block/bdev.c:793 bdev_open+0x279/0x7d0 block/bdev.c:1002 bdev_file_open_by_dev+0x1cc/0x230 block/bdev.c:1104 disk_scan_partitions+0x149/0x1b0 block/genhd.c:387 blkdev_common_ioctl+0x120d/0x2060 block/ioctl.c:713 blkdev_ioctl+0x31f/0x460 block/ioctl.c:792 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+0x239d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff86e7cde0 of 16 bytes by task 10910 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:496 [inline] desc_read_finalized_seq kernel/printk/printk_ringbuffer.c:1934 [inline] prb_read kernel/printk/printk_ringbuffer.c:1982 [inline] _prb_read_valid+0x183/0x930 kernel/printk/printk_ringbuffer.c:2173 prb_read_valid+0x3c/0x60 kernel/printk/printk_ringbuffer.c:2245 printk_get_next_message+0xea/0x550 kernel/printk/printk.c:3052 console_emit_next_record kernel/printk/printk.c:3137 [inline] console_flush_one_record kernel/printk/printk.c:3268 [inline] console_flush_all+0x2bc/0x6d0 kernel/printk/printk.c:3350 __console_flush_and_unlock kernel/printk/printk.c:3380 [inline] console_unlock+0xa1/0x280 kernel/printk/printk.c:3420 vprintk_emit+0x3e5/0x610 kernel/printk/printk.c:2479 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2504 set_capacity_and_notify+0x1d5/0x230 block/genhd.c:93 loop_set_size+0x2e/0x70 drivers/block/loop.c:221 loop_configure+0x826/0x9c0 drivers/block/loop.c:1101 lo_ioctl+0x1e3/0x1430 drivers/block/loop.c:1556 blkdev_ioctl+0x387/0x460 block/ioctl.c:798 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+0x239d/0x2550 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 10910 Comm: syz.3.3560 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 ================================================================== EXT4-fs: Ignoring removed nobh option EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #3: comm syz.3.3560: corrupted inode contents loop3: lost file I/O error report for ino 3 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): ext4_dirty_inode:6731: inode #3: comm syz.3.3560: mark_inode_dirty error loop3: lost file I/O error report for ino 3 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #3: comm syz.3.3560: corrupted inode contents loop3: lost file I/O error report for ino 3 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): __ext4_ext_dirty:207: inode #3: comm syz.3.3560: mark_inode_dirty error loop3: lost file I/O error report for ino 3 type 5 pos 0x0 len 0x0 error -117 Quota error (device loop3): write_blk: dquota write failed Quota error (device loop3): qtree_write_dquot: Error -117 occurred while creating quota EXT4-fs error (device loop3): ext4_acquire_dquot:7069: comm syz.3.3560: Failed to acquire dquot type 0 loop3: lost filesystem error report for type 5 error -117 EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #16: comm syz.3.3560: corrupted inode contents loop3: lost file I/O error report for ino 16 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): ext4_dirty_inode:6731: inode #16: comm syz.3.3560: mark_inode_dirty error loop3: lost file I/O error report for ino 16 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #16: comm syz.3.3560: corrupted inode contents loop3: lost file I/O error report for ino 16 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): __ext4_ext_dirty:207: inode #16: comm syz.3.3560: mark_inode_dirty error loop3: lost file I/O error report for ino 16 type 5 pos 0x0 len 0x0 error -117 EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #16: comm syz.3.3560: corrupted inode contents EXT4-fs error (device loop3) in ext4_orphan_del:304: Corrupt filesystem loop3: lost filesystem error report for type 5 error -117 EXT4-fs error (device loop3): ext4_do_update_inode:5801: inode #16: comm syz.3.3560: corrupted inode contents EXT4-fs error (device loop3): ext4_truncate:4721: inode #16: comm syz.3.3560: mark_inode_dirty error EXT4-fs error (device loop3) in ext4_process_orphan:346: Corrupt filesystem loop3: lost filesystem error report for type 5 error -117 EXT4-fs (loop3): 1 truncate cleaned up EXT4-fs (loop3): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.