syzbot

EXT4-fs (loop0): error count since last fsck: 1
EXT4-fs (loop0): initial error at time 1775904674: ext4_iget_extra_inode:5040: inode 15
EXT4-fs (loop0): last error at time 1775904674: ext4_iget_extrt:5040
==================================================================
BUG: KCSAN: data-race in memcpy_and_pad / string

write to 0xffff88811b7555e0 of 15 bytes by task 14673 on cpu 0:
 memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1008
 ext4_update_super+0x790/0xba0 fs/ext4/super.c:6259
 ext4_commit_super+0x40/0x280 fs/ext4/super.c:6288
 ext4_handle_error+0x452/0x550 fs/ext4/super.c:719
 __ext4_error+0x172/0x310 fs/ext4/super.c:831
 ext4_orphan_get+0x189/0x430 fs/ext4/ialloc.c:1400
 ext4_orphan_cleanup+0x5fa/0xa00 fs/ext4/orphan.c:465
 __ext4_fill_super fs/ext4/super.c:5693 [inline]
 ext4_fill_super+0x3414/0x37c0 fs/ext4/super.c:5816
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1694
 get_tree_bdev+0x1f/0x30 fs/super.c:1717
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5848
 vfs_get_tree+0x57/0x1d0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3763 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3839
 path_mount+0x4d0/0xbc0 fs/namespace.c:4159
 do_mount fs/namespace.c:4172 [inline]
 __do_sys_mount fs/namespace.c:4361 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4338
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4338
 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+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811b7555ee of 1 bytes by interrupt on cpu 1:
 string_nocheck lib/vsprintf.c:655 [inline]
 string+0x15f/0x220 lib/vsprintf.c:737
 vsnprintf+0x532/0x860 lib/vsprintf.c:2948
 vscnprintf+0x41/0x90 lib/vsprintf.c:3013
 printk_sprint+0x30/0x2e0 kernel/printk/printk.c:2222
 vprintk_store+0x57b/0x910 kernel/printk/printk.c:2364
 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
 print_daily_error_info+0x210/0x300 fs/ext4/super.c:3704
 call_timer_fn+0x3b/0x2a0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2373 [inline]
 __run_timer_base+0x426/0x620 kernel/time/timer.c:2385
 run_timer_base kernel/time/timer.c:2394 [inline]
 run_timer_softirq+0x31/0x70 kernel/time/timer.c:2404
 handle_softirqs+0xb9/0x2a0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0x39/0xc0 kernel/softirq.c:723
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x37/0x80 arch/x86/kernel/apic/apic.c:1056
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697

value changed: 0x61 -> 0x74

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14664 Comm: syz.2.3099 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
==================================================================