============================= WARNING: suspicious RCU usage 5.9.0-next-20201016-syzkaller #0 Not tainted ----------------------------- include/linux/cgroup.h:494 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 no locks held by syz-executor.0/8248. stack backtrace: CPU: 1 PID: 8248 Comm: syz-executor.0 Not tainted 5.9.0-next-20201016-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fb lib/dump_stack.c:118 task_css include/linux/cgroup.h:494 [inline] blkcg_css include/linux/blk-cgroup.h:224 [inline] blkcg_css include/linux/blk-cgroup.h:217 [inline] io_init_identity+0x3a9/0x450 fs/io_uring.c:1052 io_uring_alloc_task_context+0x176/0x250 fs/io_uring.c:7730 io_uring_add_task_file+0x10d/0x180 fs/io_uring.c:8653 io_uring_get_fd fs/io_uring.c:9144 [inline] io_uring_create fs/io_uring.c:9308 [inline] io_uring_setup+0x2727/0x3660 fs/io_uring.c:9342 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45de59 Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f258206dbf8 EFLAGS: 00000206 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 00000000200000c0 RCX: 000000000045de59 RDX: 0000000020ffa000 RSI: 00000000200000c0 RDI: 0000000000002421 RBP: 000000000118c020 R08: 0000000020000140 R09: 0000000020000140 R10: 0000000020000040 R11: 0000000000000206 R12: 0000000020ffa000 R13: 0000000020ffc000 R14: 0000000020000140 R15: 0000000020000040