EXT4-fs error (device loop6): ext4_mb_generate_buddy:1289: group 0, block bitmap and bg descriptor inconsistent: 25 vs 150994969 free clusters ================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff8687bf70 of 8 bytes by task 26123 on cpu 0: data_alloc+0x27d/0x2b0 kernel/printk/printk_ringbuffer.c:1096 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+0x248/0x320 fs/ext4/super.c:813 ext4_read_block_bitmap_nowait+0x1d5/0x680 fs/ext4/balloc.c:482 ext4_mb_init_cache+0x240/0xba0 fs/ext4/mballoc.c:1406 ext4_mb_init_group+0x25b/0x3f0 fs/ext4/mballoc.c:1612 ext4_mb_prefetch_fini+0xf3/0x160 fs/ext4/mballoc.c:2914 ext4_mb_regular_allocator+0x1511/0x15e0 fs/ext4/mballoc.c:3079 ext4_mb_new_blocks+0x800/0x2080 fs/ext4/mballoc.c:6285 ext4_ext_map_blocks+0xff5/0x38a0 fs/ext4/extents.c:4383 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_quota_write+0x167/0x360 fs/ext4/super.c:7301 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x208/0x340 fs/quota/quota_tree.c:136 do_insert_tree+0x19a/0x9b0 fs/quota/quota_tree.c:347 do_insert_tree+0x753/0x9b0 fs/quota/quota_tree.c:402 do_insert_tree+0x731/0x9b0 fs/quota/quota_tree.c:402 do_insert_tree+0x731/0x9b0 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x2cb/0x300 fs/quota/quota_tree.c:451 v2_write_dquot+0xda/0x140 fs/quota/quota_v2.c:372 dquot_acquire+0x1c0/0x2b0 fs/quota/dquot.c:470 ext4_acquire_dquot+0x15f/0x200 fs/ext4/super.c:6933 dqget+0x535/0x8d0 fs/quota/dquot.c:977 __dquot_initialize+0x20c/0x7c0 fs/quota/dquot.c:1505 dquot_initialize+0x1a/0x30 fs/quota/dquot.c:1567 ext4_evict_inode+0xd5/0xd90 fs/ext4/inode.c:192 evict+0x2e3/0x550 fs/inode.c:810 iput_final fs/inode.c:1897 [inline] iput+0x447/0x5b0 fs/inode.c:1923 ext4_process_orphan+0x1a9/0x1c0 fs/ext4/orphan.c:360 ext4_orphan_cleanup+0x6a8/0xa00 fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5609 [inline] ext4_fill_super+0x3260/0x35d0 fs/ext4/super.c:5728 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1692 get_tree_bdev+0x1f/0x30 fs/super.c:1715 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5760 vfs_get_tree+0x57/0x1d0 fs/super.c:1815 do_new_mount+0x207/0x5e0 fs/namespace.c:3808 path_mount+0x4a4/0xb20 fs/namespace.c:4123 do_mount fs/namespace.c:4136 [inline] __do_sys_mount fs/namespace.c:4347 [inline] __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4324 __x64_sys_mount+0x67/0x80 fs/namespace.c:4324 x64_sys_call+0x2b4d/0x2ff0 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 read to 0xffffffff8687bf70 of 8 bytes by task 26129 on cpu 1: desc_read kernel/printk/printk_ringbuffer.c:482 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline] prb_reserve+0x221/0xaf0 kernel/printk/printk_ringbuffer.c:1619 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_msg+0x18f/0x1a0 fs/ext4/super.c:981 mpage_map_and_submit_extent fs/ext4/inode.c:2493 [inline] ext4_do_writepages+0x1ce0/0x2750 fs/ext4/inode.c:2931 ext4_writepages+0x176/0x300 fs/ext4/inode.c:3025 do_writepages+0x1c3/0x310 mm/page-writeback.c:2634 filemap_fdatawrite_wbc mm/filemap.c:386 [inline] __filemap_fdatawrite_range mm/filemap.c:419 [inline] file_write_and_wait_range+0x156/0x2c0 mm/filemap.c:794 generic_buffers_fsync_noflush+0x45/0x120 fs/buffer.c:609 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline] ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147 vfs_fsync_range+0x10a/0x130 fs/sync.c:187 generic_write_sync include/linux/fs.h:3043 [inline] ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x527/0x960 fs/read_write.c:686 ksys_write+0xda/0x1a0 fs/read_write.c:738 __do_sys_write fs/read_write.c:749 [inline] __se_sys_write fs/read_write.c:746 [inline] __x64_sys_write+0x40/0x50 fs/read_write.c:746 x64_sys_call+0x27fe/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:2 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: 0x00000000000aa010 -> 0x0000000000157a10 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 26129 Comm: syz.6.8103 Not tainted syzkaller #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 ================================================================== EXT4-fs (loop6): Delayed block allocation failed for inode 18 at logical offset 0 with max blocks 994 with error 28 EXT4-fs (loop6): This should not happen!! Data will be lost EXT4-fs (loop6): Total free blocks count 0 EXT4-fs (loop6): Free/Dirty block details EXT4-fs (loop6): free_blocks=2415919104 EXT4-fs (loop6): dirty_blocks=1008 EXT4-fs (loop6): Block reservation details EXT4-fs (loop6): i_reserved_data_blocks=63