Messages in this thread | | | Date | Tue, 22 Jan 2013 12:02:58 +0800 | From | Li Zefan <> | Subject | perf: cgroup: INFO: suspicious RCU usage |
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Got this warning as soon as I ran "perf stat -a -e faults -G cgrp1 -- sleep 1"
This is a long-standing bug. At least I can trigger the same warning in 3.4 kernel. There were several bug reports before, but no one seems to care?
=============================== [ INFO: suspicious RCU usage. ] 3.8.0-rc2-default+ #17 Not tainted ------------------------------- include/linux/cgroup.h:534 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1 1 lock held by swapper/0/0: #0: (&cpuctx_lock){-.....}, at: [<ffffffff81115325>] perf_ctx_lock+0x15/0x30
stack backtrace: Pid: 0, comm: swapper/0 Not tainted 3.8.0-rc2-tj-0.7-default+ #17 Call Trace: <IRQ> [<ffffffff810aa863>] lockdep_rcu_suspicious+0xe3/0x130 [<ffffffff8111ea96>] __perf_install_in_context+0x1a6/0x210 [<ffffffff811148d9>] remote_function+0x49/0x60 [<ffffffff810b4877>] ? generic_smp_call_function_single_interrupt+0x57/0x120 [<ffffffff810b48e6>] generic_smp_call_function_single_interrupt+0xc6/0x120 [<ffffffff813953b0>] ? disable_cpuidle+0x20/0x20 [<ffffffff81026bf7>] smp_call_function_single_interrupt+0x27/0x40 [<ffffffff8149ebb2>] call_function_single_interrupt+0x72/0x80 <EOI> [<ffffffff81395a53>] ? cpuidle_wrap_enter+0x53/0xa0 [<ffffffff81395a4f>] ? cpuidle_wrap_enter+0x4f/0xa0 [<ffffffff81395ab0>] cpuidle_enter_tk+0x10/0x20 [<ffffffff813953e7>] cpuidle_enter_state+0x17/0x50 [<ffffffff81395d9a>] cpuidle_idle_call+0x13a/0x1c0 [<ffffffff8100b0df>] cpu_idle+0x9f/0xf0 [<ffffffff8147be7f>] rest_init+0xdf/0x160 [<ffffffff8147bda0>] ? csum_partial_copy_generic+0x170/0x170 [<ffffffff81addb3a>] start_kernel+0x372/0x442 [<ffffffff81add5c1>] ? repair_env_string+0x58/0x58 [<ffffffff8148ee7e>] ? memblock_reserve+0x2e/0x4e [<ffffffff81add2b5>] x86_64_start_reservations+0xa5/0xc2 [<ffffffff81add3e1>] x86_64_start_kernel+0x10f/0x12a [<ffffffff81add120>] ? early_idt_handlers+0x120/0x120
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