Hi Eric, The below warning shows up since commit tree: git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git userns-always-map-user-v45 head: 38a0b1b84f5f613ff4e01fffda27f87d4cb2b649 commit: 928ccdb582292cec4552bbf5831f7d374ff60269 userns: Allow unprivileged users to create new namespaces [ 0.053560] =============================== [ 0.054000] [ INFO: suspicious RCU usage. ] [ 0.055001] 3.6.0-rc1-00116-g48de0c9 #176 Not tainted [ 0.055999] ------------------------------- [ 0.057001] /c/kernel-tests/src/linux/kernel/nsproxy.c:126 suspicious rcu_dereference_check() usage! [ 0.057999] [ 0.057999] other info that might help us debug this: [ 0.057999] [ 0.058999] [ 0.058999] rcu_scheduler_active = 1, debug_locks = 1 [ 0.059998] no locks held by swapper/0. [ 0.060998] [ 0.060998] stack backtrace: [ 0.061999] Pid: 0, comm: swapper Not tainted 3.6.0-rc1-00116-g48de0c9 #176 [ 0.062999] Call Trace: [ 0.063532] [] lockdep_rcu_suspicious+0xba/0xc3 [ 0.064004] [] copy_namespaces+0x59/0x1fd [ 0.066002] [] copy_process.part.49+0xec6/0xf02 [ 0.067002] [] ? kvm_clock_read+0x18/0x26 [ 0.068004] [] ? start_kernel+0x304/0x304 [ 0.069000] [] do_fork+0xc6/0x23d [ 0.070000] [] ? trace_hardirqs_off+0xb/0xd [ 0.071001] [] ? local_clock+0x36/0x4e [ 0.072003] [] ? _raw_spin_unlock_irqrestore+0x39/0x4f [ 0.073053] [] ? start_kernel+0x304/0x304 [ 0.074002] [] kernel_thread+0x72/0x7a [ 0.074999] [] ? start_kernel+0x304/0x304 [ 0.076001] [] ? common_interrupt+0x3c/0x3c [ 0.077000] [] rest_init+0x1a/0x112 [ 0.077999] [] start_kernel+0x2ff/0x304 [ 0.079000] [] i386_start_kernel+0x78/0x7d [ 0.080376] Performance Events: unsupported Netburst CPU model 6 no PMU driver, software events only. [ 0.086440] device: 'platform': device_add Thanks, Fengguang