EXT4-fs (loop2): couldn't mount as ext3 due to feature incompatibilities
==================================================================
BUG: KCSAN: data-race in __filemap_add_folio / invalidate_bdev

read-write to 0xffff8881005f0578 of 8 bytes by task 4849 on cpu 1:
 __filemap_add_folio+0x6b7/0x910 mm/filemap.c:919
 filemap_add_folio+0x1cd/0x380 mm/filemap.c:972
 page_cache_ra_unbounded+0x1a4/0x3a0 mm/readahead.c:293
 do_page_cache_ra mm/readahead.c:348 [inline]
 force_page_cache_ra+0x190/0x1d0 mm/readahead.c:378
 page_cache_sync_ra+0x11d/0x560 mm/readahead.c:602
 filemap_get_pages+0x2f2/0x1360 mm/filemap.c:2714
 filemap_read+0x219/0xa20 mm/filemap.c:2824
 blkdev_read_iter+0x21e/0x2d0 block/fops.c:832
 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+0x2135/0x2550 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881005f0578 of 8 bytes by task 6476 on cpu 0:
 invalidate_bdev+0x25/0x70 block/bdev.c:98
 __ext4_fill_super fs/ext4/super.c:5830 [inline]
 ext4_fill_super+0x2ccb/0x37b0 fs/ext4/super.c:5855
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1887
 get_tree_bdev+0x1f/0x30 fs/super.c:1910
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5887
 vfs_get_tree+0x57/0x1d0 fs/super.c:1947
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3772 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3848
 path_mount+0x4ad/0xb90 fs/namespace.c:4168
 do_mount fs/namespace.c:4181 [inline]
 __do_sys_mount fs/namespace.c:4397 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4374
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4374
 x64_sys_call+0xc3b/0x2550 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000007 -> 0x0000000000000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6476 Comm: syz.2.1271 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
==================================================================