EXT4-fs error (device loop1): ext4_map_blocks:778: inode #15: block 3: comm syz.1.693: lblock 3 mapped to illegal pblock 3 (length 1) ================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff88e3c140 of 1 bytes by task 6096 on cpu 1: vsnprintf+0x2ce/0x890 lib/vsprintf.c:2878 vscnprintf+0x41/0x90 lib/vsprintf.c:2991 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336 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_mark_inode_dirty+0xbd/0x3f0 fs/ext4/inode.c:6512 __ext4_ext_dirty+0xdb/0x1f0 fs/ext4/extents.c:206 ext4_ext_insert_extent+0x13db/0x29b0 fs/ext4/extents.c:2192 ext4_ext_map_blocks+0x10b8/0x38a0 fs/ext4/extents.c:4404 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:7297 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x20b/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+0x753/0x9b0 fs/quota/quota_tree.c:402 do_insert_tree+0x753/0x9b0 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+0x1c3/0x2b0 fs/quota/dquot.c:470 ext4_acquire_dquot+0x15f/0x200 fs/ext4/super.c:6929 dqget+0x535/0x8d0 fs/quota/dquot.c:977 __dquot_initialize+0x27f/0x7c0 fs/quota/dquot.c:1505 dquot_initialize+0x1a/0x30 fs/quota/dquot.c:1567 ext4_process_orphan+0x32/0x1c0 fs/ext4/orphan.c:329 ext4_orphan_cleanup+0x6a8/0xa00 fs/ext4/orphan.c:474 __ext4_fill_super fs/ext4/super.c:5605 [inline] ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5724 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:5756 vfs_get_tree+0x57/0x1d0 fs/super.c:1815 do_new_mount+0x207/0x5e0 fs/namespace.c:3805 path_mount+0x4a4/0xb20 fs/namespace.c:4120 do_mount fs/namespace.c:4133 [inline] __do_sys_mount fs/namespace.c:4344 [inline] __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4321 __x64_sys_mount+0x67/0x80 fs/namespace.c:4321 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 0xffffffff88e3c140 of 8 bytes by task 6097 on cpu 0: 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+0x30f/0x3f0 fs/ext4/super.c:839 __check_block_validity fs/ext4/inode.c:390 [inline] ext4_map_blocks+0xa14/0xd00 fs/ext4/inode.c:-1 ext4_mpage_readpages+0x652/0xf10 fs/ext4/readpage.c:295 ext4_read_folio+0xc0/0x190 fs/ext4/inode.c:3393 filemap_read_folio+0x2e/0x110 mm/filemap.c:2413 filemap_fault+0x56a/0xb40 mm/filemap.c:3537 __do_fault+0xb9/0x200 mm/memory.c:5152 do_shared_fault mm/memory.c:5637 [inline] do_fault mm/memory.c:5711 [inline] do_pte_missing mm/memory.c:4234 [inline] handle_pte_fault mm/memory.c:6052 [inline] __handle_mm_fault mm/memory.c:6195 [inline] handle_mm_fault+0xd69/0x2c20 mm/memory.c:6364 do_user_addr_fault+0x636/0x1090 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 value changed: 0x00000000ffffe74c -> 0x646f6e69203a3630 Reported by Kernel Concurrency Sanitizer on: CPU: 0 UID: 0 PID: 6097 Comm: syz.1.693 Not tainted 6.17.0-rc1-syzkaller-00036-gdfc0f6373094 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 ================================================================== EXT4-fs error (device loop1): ext4_map_blocks:778: inode #15: block 3: comm syz.1.693: lblock 3 mapped to illegal pblock 3 (length 1) EXT4-fs error (device loop1): ext4_map_blocks:778: inode #15: block 3: comm syz.1.693: lblock 3 mapped to illegal pblock 3 (length 1)