============================= WARNING: suspicious RCU usage syzkaller #0 Not tainted ----------------------------- fs/btrfs/volumes.h:872 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 3 locks held by syz.2.1057/8526: #0: ffff88807cc920e0 (&type->s_umount_key#58/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:345 #1: ffff888057f2e0d8 (&fs_devs->device_list_mutex){+.+.}-{4:4}, at: btrfs_init_dev_stats+0x5b/0x190 fs/btrfs/volumes.c:8157 #2: ffff8880772940f8 (btrfs-dev-00){.+.+}-{4:4}, at: btrfs_tree_read_lock_nested+0x33/0x250 fs/btrfs/locking.c:146 stack backtrace: CPU: 0 UID: 0 PID: 8526 Comm: syz.2.1057 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 lockdep_rcu_suspicious+0x13f/0x1d0 kernel/locking/lockdep.c:6876 btrfs_dev_name fs/btrfs/volumes.h:872 [inline] btrfs_dev_stat_print_on_load fs/btrfs/volumes.c:8302 [inline] btrfs_device_init_dev_stats+0x971/0xb90 fs/btrfs/volumes.c:8140 btrfs_init_dev_stats+0x8e/0x190 fs/btrfs/volumes.c:8159 open_ctree+0x1be9/0x2e40 fs/btrfs/disk-io.c:3534 btrfs_fill_super+0x187/0x2e0 fs/btrfs/super.c:981 btrfs_get_tree_super fs/btrfs/super.c:1944 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline] btrfs_get_tree+0xe77/0x1370 fs/btrfs/super.c:2121 vfs_get_tree+0x92/0x2a0 fs/super.c:1754 fc_mount fs/namespace.c:1193 [inline] do_new_mount_fc fs/namespace.c:3763 [inline] do_new_mount+0x341/0xd30 fs/namespace.c:3839 do_mount fs/namespace.c:4172 [inline] __do_sys_mount fs/namespace.c:4361 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4338 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f197b19da0a Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f197bf8be58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f197bf8bee0 RCX: 00007f197b19da0a RDX: 0000200000005100 RSI: 0000200000000040 RDI: 00007f197bf8bea0 RBP: 0000200000005100 R08: 00007f197bf8bee0 R09: 0000000000a08811 R10: 0000000000a08811 R11: 0000000000000246 R12: 0000200000000040 R13: 00007f197bf8bea0 R14: 0000000000005163 R15: 0000200000000100 BTRFS info (device loop2 state ECS): bdev /dev/loop2 errs: wr 150994944, rd 0, flush 0, corrupt 0, gen 0 BTRFS info (device loop2 state ECS): setting nodatasum BTRFS info (device loop2 state ECS): disabling tree log BTRFS info (device loop2 state ECS): enabling free space tree BTRFS info (device loop2 state ECS): ignoring bad roots BTRFS info (device loop2 state ECS): ignoring meta csums