syzbot

loop4: detected capacity change from 0 to 512
EXT4-fs: Ignoring removed nobh option
==================================================================
BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237c275e0 of 8 bytes by task 31612 on cpu 0:
 bh_lru_install fs/buffer.c:1323 [inline]
 find_get_block_common+0x45c/0x870 fs/buffer.c:1388
 __getblk_slow fs/buffer.c:-1 [inline]
 bdev_getblk+0x310/0x3c0 fs/buffer.c:1439
 ext4_sb_breadahead_unmovable+0x45/0x170 fs/ext4/super.c:280
 ext4_group_desc_init+0x5e4/0x1560 fs/ext4/super.c:4929
 __ext4_fill_super fs/ext4/super.c:5445 [inline]
 ext4_fill_super+0x1eb8/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1634
 get_tree_bdev+0x1f/0x30 fs/super.c:1657
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1694
 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

read to 0xffff888237c275e0 of 8 bytes by task 31614 on cpu 1:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1529
 smp_call_function_many_cond+0x297/0xb60 kernel/smp.c:836
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1057
 on_each_cpu_cond include/linux/smp.h:106 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1538
 kill_bdev block/bdev.c:90 [inline]
 set_blocksize+0x1e3/0x270 block/bdev.c:207
 sb_set_blocksize+0x93/0x170 block/bdev.c:240
 sb_min_blocksize+0x53/0x60 block/bdev.c:255
 ext4_load_super fs/ext4/super.c:5137 [inline]
 __ext4_fill_super fs/ext4/super.c:5358 [inline]
 ext4_fill_super+0x39c/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1634
 get_tree_bdev+0x1f/0x30 fs/super.c:1657
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1694
 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

value changed: 0xffff88811acd97e0 -> 0xffff88811acba2a0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 31614 Comm: syz.4.7210 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
==================================================================
EXT4-fs (loop4): encrypted files will use data=ordered instead of data journaling mode
EXT4-fs (loop4): 1 truncate cleaned up
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.