BTRFS info (device loop4): enabling ssd optimizations ================================================================== BUG: KCSAN: data-race in caching_thread / find_free_extent write to 0xffff888027b81ca4 of 4 bytes by task 10088 on cpu 1: caching_thread+0xe5/0x8d0 fs/btrfs/block-group.c:671 btrfs_work_helper+0x1e2/0x380 fs/btrfs/async-thread.c:318 process_one_work+0x3e1/0x950 kernel/workqueue.c:2275 worker_thread+0x616/0xa70 kernel/workqueue.c:2421 kthread+0x20b/0x230 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 read to 0xffff888027b81ca4 of 4 bytes by task 12836 on cpu 0: find_free_extent+0xee1/0x1a30 fs/btrfs/extent-tree.c:4158 btrfs_reserve_extent+0x118/0x2c0 fs/btrfs/extent-tree.c:4292 btrfs_alloc_tree_block+0xfe/0x880 fs/btrfs/extent-tree.c:4693 alloc_tree_block_no_bg_flush fs/btrfs/ctree.c:989 [inline] __btrfs_cow_block+0x2f2/0xac0 fs/btrfs/ctree.c:1045 btrfs_cow_block+0x252/0x3a0 fs/btrfs/ctree.c:1490 commit_cowonly_roots+0x94/0x5e0 fs/btrfs/transaction.c:1225 btrfs_commit_transaction+0x95e/0x1870 fs/btrfs/transaction.c:2275 btrfs_commit_super+0x8f/0xa0 fs/btrfs/disk-io.c:4076 close_ctree+0x1af/0x4ad fs/btrfs/disk-io.c:4140 btrfs_put_super+0x21/0x30 fs/btrfs/super.c:326 generic_shutdown_super+0xde/0x210 fs/super.c:464 kill_anon_super+0x23/0x40 fs/super.c:1055 btrfs_kill_super+0x26/0x40 fs/btrfs/super.c:2347 deactivate_locked_super+0x6a/0xb0 fs/super.c:335 deactivate_super+0x85/0x90 fs/super.c:366 cleanup_mnt+0x277/0x2e0 fs/namespace.c:1118 __cleanup_mnt+0x15/0x20 fs/namespace.c:1125 task_work_run+0x8e/0x110 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x17c/0x1b0 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:302 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 12836 Comm: syz-executor.4 Not tainted 5.11.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================