EXT4-fs error (device loop1): ext4_do_update_inode:5653: inode #2: comm syz.1.2768: corrupted inode contents
EXT4-fs error (device loop1): __ext4_ext_dirty:206: inode #2: comm syz.1.2768: mark_inode_dirty error
EXT4-fs error (device loop1): ext4_do_update_inode:5653: inode #2: comm syz.1.2768: corrupted inode contents
==================================================================
BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff88e51260 of 8 bytes by task 11035 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
 find_valid_gpt block/partitions/efi.c:-1 [inline]
 efi_partition+0x12bd/0x1400 block/partitions/efi.c:720
 check_partition block/partitions/core.c:141 [inline]
 blk_add_partitions block/partitions/core.c:589 [inline]
 bdev_disk_changed+0x4b6/0xcb0 block/partitions/core.c:693
 loop_reread_partitions drivers/block/loop.c:449 [inline]
 loop_set_status+0x5d2/0x6a0 drivers/block/loop.c:1274
 loop_set_status64 drivers/block/loop.c:1370 [inline]
 lo_ioctl+0x671/0x12b0 drivers/block/loop.c:1556
 blkdev_ioctl+0x34f/0x440 block/ioctl.c:705
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xce/0x140 fs/ioctl.c:584
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:584
 x64_sys_call+0x1816/0x2ff0 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 0xffffffff88e51260 of 8 bytes by task 11039 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
 __ext4_error_inode+0x2ca/0x3f0 fs/ext4/super.c:844
 ext4_do_update_inode fs/ext4/inode.c:5653 [inline]
 ext4_mark_iloc_dirty+0x35e/0xda0 fs/ext4/inode.c:6303
 __ext4_mark_inode_dirty+0x2e2/0x3f0 fs/ext4/inode.c:6509
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6538
 __mark_inode_dirty+0x162/0x750 fs/fs-writeback.c:2527
 mark_inode_dirty_sync include/linux/fs.h:2615 [inline]
 dquot_free_space include/linux/quotaops.h:380 [inline]
 dquot_free_block include/linux/quotaops.h:390 [inline]
 ext4_mb_clear_bb fs/ext4/mballoc.c:6640 [inline]
 ext4_free_blocks+0xea9/0x1480 fs/ext4/mballoc.c:6760
 ext4_ext_map_blocks+0x11d7/0x38a0 fs/ext4/extents.c:4418
 ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
 ext4_map_blocks+0x5ee/0xd00 fs/ext4/inode.c:811
 ext4_getblk+0x114/0x510 fs/ext4/inode.c:978
 ext4_bread+0x28/0x110 fs/ext4/inode.c:1041
 ext4_append+0x16e/0x2b0 fs/ext4/namei.c:83
 ext4_add_entry+0x1053/0x1c60 fs/ext4/namei.c:2442
 ext4_add_nondir+0x4e/0x180 fs/ext4/namei.c:2784
 ext4_create+0x1ff/0x2f0 fs/ext4/namei.c:2830
 lookup_open fs/namei.c:3708 [inline]
 open_last_lookups fs/namei.c:3807 [inline]
 path_openat+0x1105/0x2170 fs/namei.c:4043
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 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: 0x00000000ffffeaa2 -> 0x00000000fffff5af

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 11039 Comm: syz.1.2768 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================
EXT4-fs error (device loop1): ext4_dirty_inode:6538: inode #2: comm syz.1.2768: mark_inode_dirty error
syz.1.2768 (11039) used greatest stack depth: 8648 bytes left