loop0: p1 < > p3
loop0: p3 size 134217728 extends beyond EOD, truncated
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / data_alloc

write to 0xffffffff86c6b080 of 8 bytes by task 26102 on cpu 0:
 data_alloc+0x2fc/0x380 kernel/printk/printk_ringbuffer.c:1129
 prb_reserve+0x8e3/0xaf0 kernel/printk/printk_ringbuffer.c:1727
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 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
 fserror_report+0x3b8/0x500 fs/fserror.c:178
 fserror_report_file_metadata include/linux/fserror.h:61 [inline]
 __ext4_error_inode+0x177/0x3a0 fs/ext4/super.c:867
 ext4_do_update_inode fs/ext4/inode.c:5742 [inline]
 ext4_mark_iloc_dirty+0x359/0xd00 fs/ext4/inode.c:6404
 ext4_orphan_del+0x698/0x6c0 fs/ext4/orphan.c:301
 ext4_truncate+0x812/0xa10 fs/ext4/inode.c:4688
 ext4_process_orphan+0x10b/0x1c0 fs/ext4/orphan.c:337
 ext4_orphan_cleanup+0x6a6/0xa10 fs/ext4/orphan.c:472
 __ext4_fill_super fs/ext4/super.c:5705 [inline]
 ext4_fill_super+0x33ab/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1634
 get_tree_bdev+0x1f/0x30 fs/super.c:1657
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1694
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3841
 path_mount+0x4ad/0xb90 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4367
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4367
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff86c6b080 of 16 bytes by task 26111 on cpu 1:
 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
 desc_update_last_finalized+0x8f/0x170 kernel/printk/printk_ringbuffer.c:1573
 prb_final_commit+0x111/0x150 kernel/printk/printk_ringbuffer.c:1842
 vprintk_store+0x6f9/0x910 kernel/printk/printk.c:2338
 vprintk_emit+0x1a4/0x600 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:555 [inline]
 blk_add_partitions block/partitions/core.c:635 [inline]
 bdev_disk_changed+0xa52/0xe20 block/partitions/core.c:695
 loop_reread_partitions drivers/block/loop.c:443 [inline]
 loop_set_status+0x5af/0x670 drivers/block/loop.c:1272
 loop_set_status64 drivers/block/loop.c:1368 [inline]
 lo_ioctl+0x66d/0x1390 drivers/block/loop.c:1554
 blkdev_ioctl+0x387/0x460 block/ioctl.c:797
 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+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 26111 Comm: syz.0.6202 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
==================================================================