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EXT4-fs (loop4): ext4_check_descriptors: Inode bitmap for group 0 overlaps block group descriptors
EXT4-fs (loop4): ext4_check_descriptors: Checksum for group 0 failed (30349!=20869)
EXT4-fs error (device loop4): ext4_get_journal_inode:5896: comm syz.4.2794: inode #1: comm syz.4.2794: 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 0xffff88811d7c1400 of 512 bytes by task 11329 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+0x178/0x210 lib/iov_iter.c:374
 copy_folio_to_iter include/linux/uio.h:204 [inline]
 filemap_read+0x407/0xa10 mm/filemap.c:2857
 blkdev_read_iter+0x22d/0x2e0 block/fops.c:855
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x6c0/0x7f0 fs/read_write.c:574
 ksys_read+0xdc/0x1a0 fs/read_write.c:717
 __do_sys_read fs/read_write.c:726 [inline]
 __se_sys_read fs/read_write.c:724 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:724
 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+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff88811d7c15f6 of 10 bytes by task 14387 on cpu 1:
 memcpy_and_pad+0x5a/0x80 lib/string_helpers.c:1009
 ext4_update_super+0x790/0xba0 fs/ext4/super.c:6267
 ext4_commit_super+0x40/0x280 fs/ext4/super.c:6296
 ext4_handle_error+0x452/0x550 fs/ext4/super.c:725
 __ext4_error+0x172/0x2e0 fs/ext4/super.c:837
 __ext4_iget+0x44c/0x23f0 fs/ext4/inode.c:5243
 ext4_get_journal_inode+0x2a/0x130 fs/ext4/super.c:5896
 ext4_calculate_overhead+0x937/0xa20 fs/ext4/super.c:4275
 __ext4_fill_super fs/ext4/super.c:5574 [inline]
 ext4_fill_super+0x288b/0x37c0 fs/ext4/super.c:5824
 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:5856
 vfs_get_tree+0x57/0x1d0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3834
 path_mount+0x4d0/0xbc0 fs/namespace.c:4154
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4360
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4360
 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/0x3b0 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: 14387 Comm: syz.4.2794 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
==================================================================
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