Hi,
I got the following error message during booting up stage.
I tried it with 3 types of AM335x CPU with different frequency (300MHz, 600MHz, 1GHz)
But it is weird that this error message only shows in 300&600 MHz, but not in 1GHz.
Is there any timing problem or something else I need to adjust in Linux kernel?
(The value in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequency is correct in each CPU model)
[ 1.529510] OMAP Watchdog Timer Rev 0x01: initial timeout 60 sec
[ 1.539276]
[ 1.540863] ===============================
[ 1.545257] [ INFO: suspicious RCU usage. ]
[ 1.549621] -------------------------------
[ 1.554016] drivers/base/power/opp.c:153 suspicious rcu_dereference_check() usage!
[ 1.561920]
[ 1.561920] other info that might help us debug this:
[ 1.561920]
[ 1.570281]
[ 1.570281] rcu_scheduler_active = 1, debug_locks = 1
[ 1.577117] 3 locks held by swapper/1:
[ 1.581024] #0: (sysdev_drivers_lock){+.+.+.}, at: [<c02516ac>] sysdev_driver_register+0x54/0x13c
[ 1.590545] #1: (&per_cpu(cpu_policy_rwsem, cpu)){+.+.+.}, at: [<c02e13a8>] lock_policy_rwsem_write+0x28/0x50
[ 1.601135] #2: (userspace_mutex){+.+...}, at: [<c02e2744>] cpufreq_governor_userspace+0xc8/0x22c
[ 1.610626]
[ 1.610626] stack backtrace:
[ 1.615203] Backtrace:
[ 1.617767] [<c001cb80>] (dump_backtrace+0x0/0x10c) from [<c03cb8fc>] (dump_stack+0x18/0x1c)
[ 1.626617] r6:00000099 r5:c04a3be8 r4:cf01b800 r3:cf01b800
[ 1.632568] [<c03cb8e4>] (dump_stack+0x0/0x1c) from [<c006ee2c>] (lockdep_rcu_suspicious+0xbc/0xc0)
[ 1.642028] [<c006ed70>] (lockdep_rcu_suspicious+0x0/0xc0) from [<c0258ee0>] (opp_get_voltage+0x90/0xc0)
[ 1.651947] r7:00000000 r6:c0ac0108 r5:c0abea80 r4:cf141580
[ 1.657897] [<c0258e50>] (opp_get_voltage+0x0/0xc0) from [<c02e4908>] (omap_target+0xb0/0x3b4)
[ 1.666900] r5:c0ac0108 r4:000493e0
[ 1.670654] [<c02e4858>] (omap_target+0x0/0x3b4) from [<c02dfdf8>] (__cpufreq_driver_target+0x5c/0x94)
[ 1.680419] [<c02dfd9c>] (__cpufreq_driver_target+0x0/0x94) from [<c02e2810>] (cpufreq_governor_userspace+0x194/0x22c)
[ 1.691589] r6:c059d870 r5:00000000 r4:cf159900
[ 1.696472] [<c02e267c>] (cpufreq_governor_userspace+0x0/0x22c) from [<c02dfeac>] (__cpufreq_governor+0x7c/0x118)
[ 1.707183] r7:c05ac550 r6:00000003 r5:cf159900 r4:cf02be08
[ 1.713134] [<c02dfe30>] (__cpufreq_governor+0x0/0x118) from [<c02e013c>] (__cpufreq_set_policy+0x1c8/0x280)
[ 1.723419] r6:00000000 r5:cf159900 r4:cf02be08 r3:00000000
[ 1.729370] [<c02dff74>] (__cpufreq_set_policy+0x0/0x280) from [<c02e0c24>] (cpufreq_add_dev_interface+0x1a4/0x238)
[ 1.740295] r8:c0abffc4 r7:cf159900 r6:00000000 r5:cf159960 r4:c059dd94
[ 1.747344] [<c02e0a80>] (cpufreq_add_dev_interface+0x0/0x238) from [<c02e1600>] (cpufreq_add_dev+0x184/0x288)
[ 1.757812] [<c02e147c>] (cpufreq_add_dev+0x0/0x288) from [<c0251710>] (sysdev_driver_register+0xb8/0x13c)
[ 1.767913] [<c0251658>] (sysdev_driver_register+0x0/0x13c) from [<c02e0780>] (cpufreq_register_driver+0x8c/0x198)
[ 1.778717] r8:00000000 r7:c05ac550 r6:c05ae240 r5:c0abffc4 r4:c059dd48
[ 1.785797] [<c02e06f4>] (cpufreq_register_driver+0x0/0x198) from [<c053ea7c>] (omap_cpufreq_init+0x90/0xb4)
[ 1.796081] r7:cf02a000 r6:c05ae240 r5:c055108c r4:c0ac0108
[ 1.802001] [<c053e9ec>] (omap_cpufreq_init+0x0/0xb4) from [<c0008784>] (do_one_initcall+0x128/0x1ac)
[ 1.811645] r4:c0550fac r3:00000000
[ 1.815429] [<c000865c>] (do_one_initcall+0x0/0x1ac) from [<c051c8a0>] (kernel_init+0x84/0x120)
[ 1.824554] [<c051c81c>] (kernel_init+0x0/0x120) from [<c0045d80>] (do_exit+0x0/0x6dc)
[ 1.832824] r5:c051c81c r4:00000000
[ 1.844116] cpuidle: using governor ladder
[ 1.852935] cpuidle: using governor menu
