syzbot

EXT4-fs (loop4): unmounting filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09.
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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d26b70 of 8 bytes by task 5172 on cpu 1:
 bh_lru_install fs/buffer.c:1348 [inline]
 find_get_block_common+0x4f0/0x960 fs/buffer.c:1413
 __find_get_block fs/buffer.c:1423 [inline]
 bdev_getblk+0x55/0x3d0 fs/buffer.c:1458
 ext4_sb_breadahead_unmovable+0x45/0x180 fs/ext4/super.c:270
 __ext4_get_inode_loc+0x709/0x930 fs/ext4/inode.c:4538
 __ext4_get_inode_loc_noinmem fs/ext4/inode.c:4568 [inline]
 __ext4_iget+0x2ea/0x1fe0 fs/ext4/inode.c:4815
 __ext4_fill_super fs/ext4/super.c:5502 [inline]
 ext4_fill_super+0x26ea/0x34e0 fs/ext4/super.c:5726
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5758
 vfs_get_tree+0x54/0x1d0 fs/super.c:1759
 do_new_mount+0x207/0x680 fs/namespace.c:3881
 path_mount+0x4a4/0xb20 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4409
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4409
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d26b70 of 8 bytes by task 3325 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1554
 smp_call_function_many_cond+0x394/0xb20 kernel/smp.c:838
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1052
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1563
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0x9a/0x1a0 block/bdev.c:712
 blkdev_put_whole block/bdev.c:719 [inline]
 bdev_release+0x2bf/0x3d0 block/bdev.c:1144
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x29b/0x650 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x131/0x1a0 kernel/task_work.c:227
 resume_user_mode_work+0x6a/0x70 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x77/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88812645a7b8 -> 0xffff88812645ab60

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3325 Comm: syz-executor Not tainted 6.15.0-rc6-syzkaller-00105-g088d13246a46 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
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