RCU stall on panda

DISCUSSION Alex Shi 5 participants 14 messages May 5, 2014 – May 22, 2014

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Arm (32-bit) Arm sub-architectures OMAP2+ support

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Alex Shi

author

2014-05-05 09:39 UTC #0 lore raw

I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519

Is it the hardware issue or a real software problem?

95.519653] INFO: rcu_sched self-detected stall on CPU^M

[   95.519866]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489] INFO: rcu_sched detected stalls on CPUs/tasks:^M
[   95.526489]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489]  (detected by 0, t=4229 jiffies, g=800, c=799, q=440)^M
[   95.526519] Task dump for CPU 1:^M
[   95.526519] swapper/1       R running      0     0      1 0x00000000^M
[   95.559844]   (t=4229 jiffies g=800 c=799 q=440)^M
[   95.564727] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15.0-rc4 #93^M
[   95.571502] [<c00133fd>] (unwind_backtrace) from [<c001076d>] (show_stack+0x11/0x14)^M
[   95.579711] [<c001076d>] (show_stack) from [<c0570465>] (dump_stack+0x75/0x88)^M
[   95.587371] [<c0570465>] (dump_stack) from [<c0084383>] (rcu_check_callbacks+0x353/0x79c)^M
[   95.596038] [<c0084383>] (rcu_check_callbacks) from [<c003e99f>] (update_process_times+0x33/0x4c)^M
[   95.605438] [<c003e99f>] (update_process_times) from [<c008e5a3>] (tick_sched_handle.isra.18+0x1f/0x48)^M
[   95.615386] [<c008e5a3>] (tick_sched_handle.isra.18) from [<c008e609>] (tick_sched_timer+0x3d/0x5c)^M
[   95.624969] [<c008e609>] (tick_sched_timer) from [<c0051a23>] (__run_hrtimer+0x67/0x310)^M
[   95.633544] [<c0051a23>] (__run_hrtimer) from [<c00525fd>] (hrtimer_interrupt+0xe1/0x214)^M
[   95.642211] [<c00525fd>] (hrtimer_interrupt) from [<c008cecb>] (tick_receive_broadcast+0x1f/0x30)^M
[   95.651611] [<c008cecb>] (tick_receive_broadcast) from [<c0011e4f>] (handle_IPI+0xb3/0x120)^M
[   95.660461] [<c0011e4f>] (handle_IPI) from [<c00085e5>] (gic_handle_irq+0x51/0x54)^M
[   95.668487] [<c00085e5>] (gic_handle_irq) from [<c057603f>] (__irq_svc+0x3f/0x64)^M
[   95.676391] Exception stack(0xee0dbf10 to 0xee0dbf58)^M
[   95.681762] bf00:                                     00000001 00000001 00000000 ee0d8c40^M
[   95.690429] bf20: 3c6bd296 00000016 3c6f8c43 00000016 eefab540 c08e0c84 00000000 c0fc7114^M
[   95.699066] bf40: 00000010 ee0dbf58 c006ef4d c0443890 40000033 ffffffff^M
[   95.706085] [<c057603f>] (__irq_svc) from [<c0443890>] (cpuidle_enter_state+0xc0/0xc4)^M
[   95.714477] [<c0443890>] (cpuidle_enter_state) from [<c0444d11>] (cpuidle_enter_state_coupled+0xe1/0x290)^M
[   95.724639] [<c0444d11>] (cpuidle_enter_state_coupled) from [<c0067cd1>] (cpu_startup_entry+0x1a5/0x494)^M
[   95.734680] [<c0067cd1>] (cpu_startup_entry) from [<80008685>] (0x80008685)^M
[   95.742095] BUG: soft lockup - CPU#1 stuck for 40s! [swapper/1:0]^M
[   95.748535] Modules linked in:^M
[   95.751770] irq event stamp: 128730^M
[   95.755462] hardirqs last  enabled at (128727): [<c044388f>] cpuidle_enter_state+0xbf/0xc4^M
[   95.764221] hardirqs last disabled at (128728): [<c0576033>] __irq_svc+0x33/0x64^M
[   95.772064] softirqs last  enabled at (128730): [<c00386cd>] irq_enter+0x59/0x60^M
[   95.779907] softirqs last disabled at (128729): [<c00386ba>] irq_enter+0x46/0x60^M
[   95.787750] ^M

my RCU and IDLE related kernel config as blow:

CONFIG_TREE_RCU=y
CONFIG_RCU_STALL_COMMON=y
CONFIG_RCU_FANOUT=32
CONFIG_RCU_FANOUT_LEAF=16
CONFIG_TREE_RCU_TRACE=y
CONFIG_PROVE_RCU=y
CONFIG_PROVE_RCU_REPEATEDLY=y CONFIG_SPARSE_RCU_POINTER=y CONFIG_RCU_CPU_STALL_TIMEOUT=21 CONFIG_RCU_CPU_STALL_INFO=y
CONFIG_RCU_TRACE=y
alexs at alex-panda:~$ cat /proc/config.gz | gunzip | grep IDLE CONFIG_NO_HZ_IDLE=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y CONFIG_GENERIC_IDLE_POLL_SETUP=y
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_GOV_LADDER=y CONFIG_CPU_IDLE_GOV_MENU=y CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED=y

Signature · 2 lines

Thanks
    Alex

Paul E. McKenney

2014-05-05 18:06 UTC #1 lore raw

Quoted 4 lines · Alex Shi

I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?

I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.

Thanx, Paul

Quoted 65 lines

95.519653] INFO: rcu_sched self-detected stall on CPU^M

[   95.519866]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489] INFO: rcu_sched detected stalls on CPUs/tasks:^M
[   95.526489]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489]  (detected by 0, t=4229 jiffies, g=800, c=799, q=440)^M
[   95.526519] Task dump for CPU 1:^M
[   95.526519] swapper/1       R running      0     0      1 0x00000000^M
[   95.559844]   (t=4229 jiffies g=800 c=799 q=440)^M
[   95.564727] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15.0-rc4 #93^M
[   95.571502] [<c00133fd>] (unwind_backtrace) from [<c001076d>] (show_stack+0x11/0x14)^M
[   95.579711] [<c001076d>] (show_stack) from [<c0570465>] (dump_stack+0x75/0x88)^M
[   95.587371] [<c0570465>] (dump_stack) from [<c0084383>] (rcu_check_callbacks+0x353/0x79c)^M
[   95.596038] [<c0084383>] (rcu_check_callbacks) from [<c003e99f>] (update_process_times+0x33/0x4c)^M
[   95.605438] [<c003e99f>] (update_process_times) from [<c008e5a3>] (tick_sched_handle.isra.18+0x1f/0x48)^M
[   95.615386] [<c008e5a3>] (tick_sched_handle.isra.18) from [<c008e609>] (tick_sched_timer+0x3d/0x5c)^M
[   95.624969] [<c008e609>] (tick_sched_timer) from [<c0051a23>] (__run_hrtimer+0x67/0x310)^M
[   95.633544] [<c0051a23>] (__run_hrtimer) from [<c00525fd>] (hrtimer_interrupt+0xe1/0x214)^M
[   95.642211] [<c00525fd>] (hrtimer_interrupt) from [<c008cecb>] (tick_receive_broadcast+0x1f/0x30)^M
[   95.651611] [<c008cecb>] (tick_receive_broadcast) from [<c0011e4f>] (handle_IPI+0xb3/0x120)^M
[   95.660461] [<c0011e4f>] (handle_IPI) from [<c00085e5>] (gic_handle_irq+0x51/0x54)^M
[   95.668487] [<c00085e5>] (gic_handle_irq) from [<c057603f>] (__irq_svc+0x3f/0x64)^M
[   95.676391] Exception stack(0xee0dbf10 to 0xee0dbf58)^M
[   95.681762] bf00:                                     00000001 00000001 00000000 ee0d8c40^M
[   95.690429] bf20: 3c6bd296 00000016 3c6f8c43 00000016 eefab540 c08e0c84 00000000 c0fc7114^M
[   95.699066] bf40: 00000010 ee0dbf58 c006ef4d c0443890 40000033 ffffffff^M
[   95.706085] [<c057603f>] (__irq_svc) from [<c0443890>] (cpuidle_enter_state+0xc0/0xc4)^M
[   95.714477] [<c0443890>] (cpuidle_enter_state) from [<c0444d11>] (cpuidle_enter_state_coupled+0xe1/0x290)^M
[   95.724639] [<c0444d11>] (cpuidle_enter_state_coupled) from [<c0067cd1>] (cpu_startup_entry+0x1a5/0x494)^M
[   95.734680] [<c0067cd1>] (cpu_startup_entry) from [<80008685>] (0x80008685)^M
[   95.742095] BUG: soft lockup - CPU#1 stuck for 40s! [swapper/1:0]^M
[   95.748535] Modules linked in:^M
[   95.751770] irq event stamp: 128730^M
[   95.755462] hardirqs last  enabled at (128727): [<c044388f>] cpuidle_enter_state+0xbf/0xc4^M
[   95.764221] hardirqs last disabled at (128728): [<c0576033>] __irq_svc+0x33/0x64^M
[   95.772064] softirqs last  enabled at (128730): [<c00386cd>] irq_enter+0x59/0x60^M
[   95.779907] softirqs last disabled at (128729): [<c00386ba>] irq_enter+0x46/0x60^M
[   95.787750] ^M

my RCU and IDLE related kernel config as blow:

Signature · 2 lines

Thanks
    Alex

Tony Lindgren

maintainer

2014-05-12 21:21 UTC #2 lore raw

Quoted 10 lines · Paul E. McKenney

Quoted 4 lines · Alex Shi
I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?
I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.

Looks like you have CPU_IDLE enabled on panda. Hangs with current linux next with CPU_IDLE are currently being discussed on the linux-omap list in thread "omap4-panda-es boot issues with v3.15-rc4"

I've seen occasional system hangs, and I've also noticed that doing ctrl-a-f h or ctrl-a-f l for sysrq backtrace can unlock the system producing similar errors to the below.

Regards,

Tony

Quoted 71 lines

Quoted 52 lines

95.519653] INFO: rcu_sched self-detected stall on CPU^M

[   95.519866]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489] INFO: rcu_sched detected stalls on CPUs/tasks:^M
[   95.526489]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489]  (detected by 0, t=4229 jiffies, g=800, c=799, q=440)^M
[   95.526519] Task dump for CPU 1:^M
[   95.526519] swapper/1       R running      0     0      1 0x00000000^M
[   95.559844]   (t=4229 jiffies g=800 c=799 q=440)^M
[   95.564727] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15.0-rc4 #93^M
[   95.571502] [<c00133fd>] (unwind_backtrace) from [<c001076d>] (show_stack+0x11/0x14)^M
[   95.579711] [<c001076d>] (show_stack) from [<c0570465>] (dump_stack+0x75/0x88)^M
[   95.587371] [<c0570465>] (dump_stack) from [<c0084383>] (rcu_check_callbacks+0x353/0x79c)^M
[   95.596038] [<c0084383>] (rcu_check_callbacks) from [<c003e99f>] (update_process_times+0x33/0x4c)^M
[   95.605438] [<c003e99f>] (update_process_times) from [<c008e5a3>] (tick_sched_handle.isra.18+0x1f/0x48)^M
[   95.615386] [<c008e5a3>] (tick_sched_handle.isra.18) from [<c008e609>] (tick_sched_timer+0x3d/0x5c)^M
[   95.624969] [<c008e609>] (tick_sched_timer) from [<c0051a23>] (__run_hrtimer+0x67/0x310)^M
[   95.633544] [<c0051a23>] (__run_hrtimer) from [<c00525fd>] (hrtimer_interrupt+0xe1/0x214)^M
[   95.642211] [<c00525fd>] (hrtimer_interrupt) from [<c008cecb>] (tick_receive_broadcast+0x1f/0x30)^M
[   95.651611] [<c008cecb>] (tick_receive_broadcast) from [<c0011e4f>] (handle_IPI+0xb3/0x120)^M
[   95.660461] [<c0011e4f>] (handle_IPI) from [<c00085e5>] (gic_handle_irq+0x51/0x54)^M
[   95.668487] [<c00085e5>] (gic_handle_irq) from [<c057603f>] (__irq_svc+0x3f/0x64)^M
[   95.676391] Exception stack(0xee0dbf10 to 0xee0dbf58)^M
[   95.681762] bf00:                                     00000001 00000001 00000000 ee0d8c40^M
[   95.690429] bf20: 3c6bd296 00000016 3c6f8c43 00000016 eefab540 c08e0c84 00000000 c0fc7114^M
[   95.699066] bf40: 00000010 ee0dbf58 c006ef4d c0443890 40000033 ffffffff^M
[   95.706085] [<c057603f>] (__irq_svc) from [<c0443890>] (cpuidle_enter_state+0xc0/0xc4)^M
[   95.714477] [<c0443890>] (cpuidle_enter_state) from [<c0444d11>] (cpuidle_enter_state_coupled+0xe1/0x290)^M
[   95.724639] [<c0444d11>] (cpuidle_enter_state_coupled) from [<c0067cd1>] (cpu_startup_entry+0x1a5/0x494)^M
[   95.734680] [<c0067cd1>] (cpu_startup_entry) from [<80008685>] (0x80008685)^M
[   95.742095] BUG: soft lockup - CPU#1 stuck for 40s! [swapper/1:0]^M
[   95.748535] Modules linked in:^M
[   95.751770] irq event stamp: 128730^M
[   95.755462] hardirqs last  enabled at (128727): [<c044388f>] cpuidle_enter_state+0xbf/0xc4^M
[   95.764221] hardirqs last disabled at (128728): [<c0576033>] __irq_svc+0x33/0x64^M
[   95.772064] softirqs last  enabled at (128730): [<c00386cd>] irq_enter+0x59/0x60^M
[   95.779907] softirqs last disabled at (128729): [<c00386ba>] irq_enter+0x46/0x60^M
[   95.787750] ^M

my RCU and IDLE related kernel config as blow:

Quoted 13 lines

alexs at alex-panda:~$ cat /proc/config.gz | gunzip | grep IDLE CONFIG_NO_HZ_IDLE=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y CONFIG_GENERIC_IDLE_POLL_SETUP=y
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_GOV_LADDER=y CONFIG_CPU_IDLE_GOV_MENU=y CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED=y
Signature · 2 lines
Thanks
    Alex

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Alex Shi

author

2014-05-13 06:36 UTC #3 lore raw

Quoted 12 lines · Tony Lindgren

Quoted 10 lines · Paul E. McKenney
Quoted 4 lines · Alex Shi
I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?
I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.

Quoted 8 lines

Looks like you have CPU_IDLE enabled on panda. Hangs with current linux next with CPU_IDLE are currently being discussed on the linux-omap list in thread "omap4-panda-es boot issues with v3.15-rc4"
I've seen occasional system hangs, and I've also noticed that doing ctrl-a-f h or ctrl-a-f l for sysrq backtrace can unlock the system producing similar errors to the below.

Thanks a lot for the info.
In fact, the oops keeps in upstream kernel from 3.10 to latest.

Quoted 75 lines

Regards,

Tony

Quoted 71 lines

Quoted 52 lines

95.519653] INFO: rcu_sched self-detected stall on CPU^M

[   95.519866]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489] INFO: rcu_sched detected stalls on CPUs/tasks:^M
[   95.526489]  1: (1 GPs behind) idle=2e7/1/0 softirq=4404/4405 ^M
[   95.526489]  (detected by 0, t=4229 jiffies, g=800, c=799, q=440)^M
[   95.526519] Task dump for CPU 1:^M
[   95.526519] swapper/1       R running      0     0      1 0x00000000^M
[   95.559844]   (t=4229 jiffies g=800 c=799 q=440)^M
[   95.564727] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.15.0-rc4 #93^M
[   95.571502] [<c00133fd>] (unwind_backtrace) from [<c001076d>] (show_stack+0x11/0x14)^M
[   95.579711] [<c001076d>] (show_stack) from [<c0570465>] (dump_stack+0x75/0x88)^M
[   95.587371] [<c0570465>] (dump_stack) from [<c0084383>] (rcu_check_callbacks+0x353/0x79c)^M
[   95.596038] [<c0084383>] (rcu_check_callbacks) from [<c003e99f>] (update_process_times+0x33/0x4c)^M
[   95.605438] [<c003e99f>] (update_process_times) from [<c008e5a3>] (tick_sched_handle.isra.18+0x1f/0x48)^M
[   95.615386] [<c008e5a3>] (tick_sched_handle.isra.18) from [<c008e609>] (tick_sched_timer+0x3d/0x5c)^M
[   95.624969] [<c008e609>] (tick_sched_timer) from [<c0051a23>] (__run_hrtimer+0x67/0x310)^M
[   95.633544] [<c0051a23>] (__run_hrtimer) from [<c00525fd>] (hrtimer_interrupt+0xe1/0x214)^M
[   95.642211] [<c00525fd>] (hrtimer_interrupt) from [<c008cecb>] (tick_receive_broadcast+0x1f/0x30)^M
[   95.651611] [<c008cecb>] (tick_receive_broadcast) from [<c0011e4f>] (handle_IPI+0xb3/0x120)^M
[   95.660461] [<c0011e4f>] (handle_IPI) from [<c00085e5>] (gic_handle_irq+0x51/0x54)^M
[   95.668487] [<c00085e5>] (gic_handle_irq) from [<c057603f>] (__irq_svc+0x3f/0x64)^M
[   95.676391] Exception stack(0xee0dbf10 to 0xee0dbf58)^M
[   95.681762] bf00:                                     00000001 00000001 00000000 ee0d8c40^M
[   95.690429] bf20: 3c6bd296 00000016 3c6f8c43 00000016 eefab540 c08e0c84 00000000 c0fc7114^M
[   95.699066] bf40: 00000010 ee0dbf58 c006ef4d c0443890 40000033 ffffffff^M
[   95.706085] [<c057603f>] (__irq_svc) from [<c0443890>] (cpuidle_enter_state+0xc0/0xc4)^M
[   95.714477] [<c0443890>] (cpuidle_enter_state) from [<c0444d11>] (cpuidle_enter_state_coupled+0xe1/0x290)^M
[   95.724639] [<c0444d11>] (cpuidle_enter_state_coupled) from [<c0067cd1>] (cpu_startup_entry+0x1a5/0x494)^M
[   95.734680] [<c0067cd1>] (cpu_startup_entry) from [<80008685>] (0x80008685)^M
[   95.742095] BUG: soft lockup - CPU#1 stuck for 40s! [swapper/1:0]^M
[   95.748535] Modules linked in:^M
[   95.751770] irq event stamp: 128730^M
[   95.755462] hardirqs last  enabled at (128727): [<c044388f>] cpuidle_enter_state+0xbf/0xc4^M
[   95.764221] hardirqs last disabled at (128728): [<c0576033>] __irq_svc+0x33/0x64^M
[   95.772064] softirqs last  enabled at (128730): [<c00386cd>] irq_enter+0x59/0x60^M
[   95.779907] softirqs last disabled at (128729): [<c00386ba>] irq_enter+0x46/0x60^M
[   95.787750] ^M

my RCU and IDLE related kernel config as blow:

Quoted 13 lines

alexs at alex-panda:~$ cat /proc/config.gz | gunzip | grep IDLE CONFIG_NO_HZ_IDLE=y
CONFIG_GENERIC_SMP_IDLE_THREAD=y CONFIG_GENERIC_IDLE_POLL_SETUP=y
CONFIG_CPU_IDLE=y
CONFIG_CPU_IDLE_GOV_LADDER=y CONFIG_CPU_IDLE_GOV_MENU=y CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED=y
Signature · 2 lines
Thanks
    Alex

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

Signature · 2 lines

Thanks
    Alex

Tony Lindgren

maintainer

2014-05-13 15:32 UTC #4 lore raw

Quoted 17 lines · Alex Shi

Quoted 16 lines · Tony Lindgren
Quoted 10 lines · Paul E. McKenney
Quoted 4 lines · Alex Shi
I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?
I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.
Looks like you have CPU_IDLE enabled on panda. Hangs with current linux next with CPU_IDLE are currently being discussed on the linux-omap list in thread "omap4-panda-es boot issues with v3.15-rc4"

Quoted 7 lines

Quoted 4 lines
I've seen occasional system hangs, and I've also noticed that doing ctrl-a-f h or ctrl-a-f l for sysrq backtrace can unlock the system producing similar errors to the below.
Thanks a lot for the info.
In fact, the oops keeps in upstream kernel from 3.10 to latest.

Care to test if the revert of commit cb7094 Santosh posted as "[PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled" solves the problem for you?

Regards,

Tony

Alex Shi

author

2014-05-15 08:44 UTC #5 lore raw

Quoted 23 lines · Tony Lindgren

Quoted 22 lines · Alex Shi
Quoted 20 lines · Tony Lindgren
Quoted 10 lines · Paul E. McKenney
Quoted 4 lines · Alex Shi
I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?
I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.
Looks like you have CPU_IDLE enabled on panda. Hangs with current linux next with CPU_IDLE are currently being discussed on the linux-omap list in thread "omap4-panda-es boot issues with v3.15-rc4"
I've seen occasional system hangs, and I've also noticed that doing ctrl-a-f h or ctrl-a-f l for sysrq backtrace can unlock the system producing similar errors to the below.

Quoted 7 lines

Quoted 2 lines
Thanks a lot for the info.
In fact, the oops keeps in upstream kernel from 3.10 to latest.
Care to test if the revert of commit cb7094 Santosh posted as "[PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled" solves the problem for you?

After enable this patch, system maybe hang in idle. :(

Quoted 4 lines

Regards,
Tony

Signature · 2 lines

Thanks
    Alex

Daniel Lezcano

2014-05-15 09:05 UTC #6 lore raw

Quoted 27 lines · Alex Shi

Quoted 26 lines · Tony Lindgren
Quoted 24 lines · Alex Shi
Quoted 12 lines · Tony Lindgren
Quoted 10 lines · Paul E. McKenney
Quoted 4 lines · Alex Shi
I keep seeing the RCU stall problem on panda board from 3.10 kernel to latest upstream kernel and google find some one report it before: https://lkml.org/lkml/2012/9/20/519
Is it the hardware issue or a real software problem?
I cannot distinguish between hardware and software from the trace below, but given that you are also seeing a soft lockup, either way you do appear to have a real problem as opposed to an RCU CPU stall warning false positive.
Quoted 8 lines
Looks like you have CPU_IDLE enabled on panda. Hangs with current linux next with CPU_IDLE are currently being discussed on the linux-omap list in thread "omap4-panda-es boot issues with v3.15-rc4"
I've seen occasional system hangs, and I've also noticed that doing ctrl-a-f h or ctrl-a-f l for sysrq backtrace can unlock the system producing similar errors to the below.
Thanks a lot for the info.
In fact, the oops keeps in upstream kernel from 3.10 to latest.

Quoted 6 lines

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Care to test if the revert of commit cb7094 Santosh posted as "[PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled" solves the problem for you?
After enable this patch, system maybe hang in idle. :(

Hi Alex,

do you mean even with this revert applied, the board hangs in idle ?

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Alex Shi

author

2014-05-15 13:26 UTC #7 lore raw

Quoted 8 lines · Daniel Lezcano

Quoted 3 lines
Quoted 1 line
After enable this patch, system maybe hang in idle. :(
Hi Alex,
do you mean even with this revert applied, the board hangs in idle ?

yes.
My board is panda ES. without this revert, it works.

Signature · 2 lines

Thanks
    Alex

Tony Lindgren

maintainer

2014-05-15 18:32 UTC #8 lore raw

Quoted 5 lines · Alex Shi

Quoted 4 lines · Daniel Lezcano
Quoted 3 lines
Quoted 1 line
After enable this patch, system maybe hang in idle. :(

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Hi Alex,
do you mean even with this revert applied, the board hangs in idle ?
yes.
My board is panda ES. without this revert, it works.

Care to specify what linux version you are testing against?

Does it hang in idle always immediately on booting?

Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?

Regards,

Tony

Santosh Shilimkar

2014-05-15 18:36 UTC #9 lore raw

Quoted 14 lines · Tony Lindgren

Quoted 5 lines · Alex Shi
Quoted 4 lines · Daniel Lezcano
Quoted 3 lines
Quoted 1 line
After enable this patch, system maybe hang in idle. :(
Quoted 7 lines
Quoted 4 lines
Hi Alex,
do you mean even with this revert applied, the board hangs in idle ?
yes.
My board is panda ES. without this revert, it works.

Quoted 8 lines

Care to specify what linux version you are testing against?
Does it hang in idle always immediately on booting?
Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?

I just posted an updated patch Alex on other thread. Attaching here again for your reference. Please try it out and see if the you still get a hang.

Regards,
Santosh

Quoted 1 line

From bb3b82cc5645b83bedf1343d03cc956f27f6fc83 Mon Sep 17 00:00:00 2001

From: Santosh Shilimkar <[email protected]>
Date: Mon, 12 May 2014 17:37:59 -0400
Subject: [PATCH] ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled

On OMAP4 panda board, there have been several bug reports about boot hang and lock-ups with CPU_IDLE enabled. The root cause of the issue is missing interrupts while in idle state. Commit cb7094e8 {cpuidle / omap4 :
use CPUIDLE_FLAG_TIMER_STOP flag} moved the broadcast notifiers to common code for right reasons but on OMAP4 which suffers from a nasty ROM code bug with GIC, commit ff999b8a {ARM: OMAP4460: Workaround for ROM bug ..}, we loose interrupts which leads to issues like lock-up, hangs etc.

Patch reverts commit cb7094 {cpuidle / omap4 : use CPUIDLE_FLAG_TIMER_STOP flag} and 54769d6 {cpuidle: OMAP4: remove timer broadcast initialization} to avoid the issue. With this change, OMAP4 panda boards, the mentioned issues are getting fixed. We no longer loose interrupts which was the cause of the regression.

Cc Roger Quadros <[email protected]>

Cc Kevin Hilman <[email protected]>

Cc Tony Lindgren <[email protected]>

Cc Daniel Lezcano <[email protected]>

Reported-tested-by Roger Quadros <[email protected]>

Reported-tested-by Kevin Hilman <[email protected]>

Tested-by Tony Lindgren <[email protected]>

Signed-off-by Santosh Shilimkar <[email protected]>

---
 arch/arm/mach-omap2/cpuidle44xx.c |   25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

arch/arm/mach-omap2/cpuidle44xx.c +21 -4

index 01fc710..2498ab0 100644
@@ -14,6 +14,7 @@
 #include <linux/cpuidle.h>
 #include <linux/cpu_pm.h>
 #include <linux/export.h>
+#include <linux/clockchips.h>
 
 #include <asm/cpuidle.h>
 #include <asm/proc-fns.h>

@@ -83,6 +84,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev,
 {
 	struct idle_statedata *cx = state_ptr + index;
 	u32 mpuss_can_lose_context = 0;
+	int cpu_id = smp_processor_id();
 
 	/*
 	 * CPU0 has to wait and stay ON until CPU1 is OFF state.

@@ -110,6 +112,8 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev,
 	mpuss_can_lose_context = (cx->mpu_state == PWRDM_POWER_RET) &&
 				 (cx->mpu_logic_state == PWRDM_POWER_OFF);
 
+	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
+
 	/*
 	 * Call idle CPU PM enter notifier chain so that
 	 * VFP and per CPU interrupt context is saved.

@@ -165,6 +169,8 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev,
 	if (dev->cpu == 0 && mpuss_can_lose_context)
 		cpu_cluster_pm_exit();
 
+	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);
+
 fail:
 	cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
 	cpu_done[dev->cpu] = false;

@@ -172,6 +178,16 @@ fail:
 	return index;
 }
 
+/*
+ * For each cpu, setup the broadcast timer because local timers
+ * stops for the states above C1.
+ */
+static void omap_setup_broadcast_timer(void *arg)
+{
+	int cpu = smp_processor_id();
+	clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
+}
+
 static struct cpuidle_driver omap4_idle_driver = {
 	.name				= "omap4_idle",
 	.owner				= THIS_MODULE,

@@ -189,8 +205,7 @@ static struct cpuidle_driver omap4_idle_driver = {
 			/* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
 			.exit_latency = 328 + 440,
 			.target_residency = 960,
-			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
-			         CPUIDLE_FLAG_TIMER_STOP,
+			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,
 			.enter = omap_enter_idle_coupled,
 			.name = "C2",
 			.desc = "CPUx OFF, MPUSS CSWR",

@@ -199,8 +214,7 @@ static struct cpuidle_driver omap4_idle_driver = {
 			/* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
 			.exit_latency = 460 + 518,
 			.target_residency = 1100,
-			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
-			         CPUIDLE_FLAG_TIMER_STOP,
+			.flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,
 			.enter = omap_enter_idle_coupled,
 			.name = "C3",
 			.desc = "CPUx OFF, MPUSS OSWR",

@@ -231,5 +245,8 @@ int __init omap4_idle_init(void)
 	if (!cpu_clkdm[0] || !cpu_clkdm[1])
 		return -ENODEV;
 
+	/* Configure the broadcast timer on each cpu */
+	on_each_cpu(omap_setup_broadcast_timer, NULL, 1);
+
 	return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
 }

Signature · 9 lines

1.7.9.5

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Alex Shi

author

2014-05-16 07:41 UTC #10 lore raw

Quoted 7 lines · Santosh Shilimkar

Quoted 7 lines
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yes.
My board is panda ES. without this revert, it works.
Care to specify what linux version you are testing against?
Does it hang in idle always immediately on booting?

Quoted 7 lines

Quoted 4 lines
Quoted 4 lines
Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?
I just posted an updated patch Alex on other thread. Attaching here again for your reference. Please try it out and see if the you still get a hang.

it does not hang this time.

but I am not sure it can solve my problem, since RCU stall is not easy to reproduce in short time.

Signature · 2 lines

Thanks
    Alex

Santosh Shilimkar

2014-05-16 13:37 UTC #11 lore raw

Quoted 12 lines · Alex Shi

Quoted 11 lines · Santosh Shilimkar
Quoted 11 lines
Quoted 11 lines
Quoted 2 lines
Quoted 2 lines
yes.
My board is panda ES. without this revert, it works.
Care to specify what linux version you are testing against?
Does it hang in idle always immediately on booting?
Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?

Quoted 6 lines

Quoted 3 lines
I just posted an updated patch Alex on other thread. Attaching here again for your reference. Please try it out and see if the you still get a hang.
it does not hang this time.

This is good news and exactly what I expected.

Quoted 3 lines

but I am not sure it can solve my problem, since RCU stall is not easy to reproduce in short time.

You may want to run the system longer if you can. I suspect the RCU stall was also side effect of missing interrupts.

Regards,
Santosh

Alex Shi

author

2014-05-22 08:59 UTC #12 lore raw

Quoted 19 lines · Santosh Shilimkar

Quoted 12 lines · Alex Shi
Quoted 11 lines · Santosh Shilimkar
Quoted 11 lines
Quoted 11 lines
Quoted 2 lines
Quoted 2 lines
yes.
My board is panda ES. without this revert, it works.
Care to specify what linux version you are testing against?
Does it hang in idle always immediately on booting?
Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?
Quoted 6 lines
Quoted 3 lines
I just posted an updated patch Alex on other thread. Attaching here again for your reference. Please try it out and see if the you still get a hang.
it does not hang this time.

Quoted 7 lines

This is good news and exactly what I expected.
Quoted 3 lines
but I am not sure it can solve my problem, since RCU stall is not easy to reproduce in short time.
You may want to run the system longer if you can. I suspect the RCU stall was also side effect of missing interrupts.

Sure. it do remove the RCU stall on my panda board.

Quoted 4 lines

Regards,
Santosh

Signature · 2 lines

Thanks
    Alex

Santosh Shilimkar

2014-05-22 13:36 UTC #13 lore raw

Quoted 22 lines · Alex Shi

Quoted 21 lines · Santosh Shilimkar
Quoted 12 lines · Alex Shi
Quoted 11 lines · Santosh Shilimkar
Quoted 11 lines
Quoted 11 lines
Quoted 2 lines
Quoted 2 lines
yes.
My board is panda ES. without this revert, it works.
Care to specify what linux version you are testing against?
Does it hang in idle always immediately on booting?
Or does the serial console first hang with sysrq still working (ctrl-a h in minicom for help) with device eventually locking up hard?
Quoted 6 lines
Quoted 3 lines
I just posted an updated patch Alex on other thread. Attaching here again for your reference. Please try it out and see if the you still get a hang.
it does not hang this time.
This is good news and exactly what I expected.

Quoted 8 lines

Quoted 5 lines
Quoted 3 lines
but I am not sure it can solve my problem, since RCU stall is not easy to reproduce in short time.
You may want to run the system longer if you can. I suspect the RCU stall was also side effect of missing interrupts.
Sure. it do remove the RCU stall on my panda board.

Thanks for confirming. Tony already send fix upstream so it should show up in next rc mostly