EXT4-fs error (device loop4): ext4_get_journal_inode:5900: comm syz.4.365: inode #1: comm syz.4.365: iget: illegal inode #
loop4: lost filesystem error report for type 5 error -117
==================================================================
BUG: KCSAN: data-race in _copy_to_iter / memcpy_and_pad

read to 0xffff88811b8ea400 of 1024 bytes by task 3689 on cpu 0:
 instrument_copy_to_user include/linux/instrumented.h:130 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
 iterate_and_advance include/linux/iov_iter.h:330 [inline]
 _copy_to_iter+0x130/0xea0 lib/iov_iter.c:197
 copy_page_to_iter+0x174/0x210 lib/iov_iter.c:374
 copy_folio_to_iter include/linux/uio.h:204 [inline]
 filemap_read+0x3ed/0xa20 mm/filemap.c:2871
 blkdev_read_iter+0x21e/0x2d0 block/fops.c:830
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x699/0x7c0 fs/read_write.c:574
 ksys_read+0xdc/0x1a0 fs/read_write.c:716
 __do_sys_read fs/read_write.c:725 [inline]
 __se_sys_read fs/read_write.c:723 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:723
 x64_sys_call+0x2886/0x3020 arch/x86/include/generated/asm/syscalls_64.h:1
 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

write to 0xffff88811b8ea5e0 of 22 bytes by task 4756 on cpu 1:
 memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1008
 ext4_update_super+0x790/0xba0 fs/ext4/super.c:6276
 ext4_commit_super+0x40/0x260 fs/ext4/super.c:6305
 ext4_handle_error+0x46f/0x570 fs/ext4/super.c:725
 __ext4_error+0x172/0x2e0 fs/ext4/super.c:837
 __ext4_iget+0x456/0x2400 fs/ext4/inode.c:5295
 ext4_get_journal_inode+0x2a/0x130 fs/ext4/super.c:5900
 ext4_calculate_overhead+0x939/0xa20 fs/ext4/super.c:4278
 __ext4_fill_super fs/ext4/super.c:5578 [inline]
 ext4_fill_super+0x2819/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1640
 get_tree_bdev+0x1f/0x30 fs/super.c:1663
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1700
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 4756 Comm: syz.4.365 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================
EXT4-fs (loop4): no journal found
EXT4-fs (loop4): can't get journal size
EXT4-fs (loop4): failed to initialize system zone (-22)
EXT4-fs (loop4): mount failed