[PATCH v1 0/2] exynos_mct driver: fix irq allocation and cleanup

From: Tarek Dakhran
Date: Wed Feb 12 2014 - 22:12:03 EST

exynos4_local_timer_setup called on the secondary cpu before
irqs are enabled. request_irq can sleep, which produces next warning:

on boot:
[ 0.370000] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[ 0.370000] Setting up static identity map for 0x403b5700 - 0x403b5758
[ 0.395000] CPU1: Booted secondary processor
[ 0.395000] ------------[ cut here ]------------
[ 0.395000] WARNING: CPU: 1 PID: 0 at kernel/locking/lockdep.c:2742 lockdep_trace_alloc+0xe0/0xfc()
[ 0.395000] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))
[ 0.395000] Modules linked in:
[ 0.395000] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.14.0-rc2-00004-g0db95f4 #128
[ 0.395000] [<c0014308>] (unwind_backtrace) from [<c0011690>] (show_stack+0x10/0x14)
[ 0.395000] [<c0011690>] (show_stack) from [<c03ae7d0>] (dump_stack+0x6c/0xb8)
[ 0.395000] [<c03ae7d0>] (dump_stack) from [<c001d504>] (warn_slowpath_common+0x68/0x8c)
[ 0.395000] [<c001d504>] (warn_slowpath_common) from [<c001d5bc>] (warn_slowpath_fmt+0x30/0x40)
[ 0.395000] [<c001d5bc>] (warn_slowpath_fmt) from [<c0059824>] (lockdep_trace_alloc+0xe0/0xfc)
[ 0.395000] [<c0059824>] (lockdep_trace_alloc) from [<c00bee24>] (kmem_cache_alloc+0x24/0x160)
[ 0.395000] [<c00bee24>] (kmem_cache_alloc) from [<c0068174>] (request_threaded_irq+0x64/0x130)
[ 0.395000] [<c0068174>] (request_threaded_irq) from [<c02efaf8>] (exynos4_local_timer_setup+0xd0/0x124)
[ 0.395000] [<c02efaf8>] (exynos4_local_timer_setup) from [<c02efc34>] (exynos4_mct_cpu_notify+0x78/0xf0)
[ 0.395000] [<c02efc34>] (exynos4_mct_cpu_notify) from [<c003d318>] (notifier_call_chain+0x44/0x84)
[ 0.395000] [<c003d318>] (notifier_call_chain) from [<c001d61c>] (__cpu_notify+0x24/0x40)
[ 0.395000] [<c001d61c>] (__cpu_notify) from [<c0013314>] (secondary_start_kernel+0xe4/0x134)
[ 0.395000] [<c0013314>] (secondary_start_kernel) from [<40008624>] (0x40008624)
[ 0.395000] ---[ end trace 347890460e745f50 ]---
[ 0.420000] CPU1: update cpu_power 1024
[ 0.420000] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001

on hotplug:
[ 108.040000] CPU3: Booted secondary processor
[ 108.040000] BUG: sleeping function called from invalid context at mm/slub.c:965
[ 108.040000] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/3
[ 108.040000] INFO: lockdep is turned off.
[ 108.040000] irq event stamp: 0
[ 108.040000] hardirqs last enabled at (0): [< (null)>] (null)
[ 108.040000] hardirqs last disabled at (0): [<c001b768>] copy_process.part.2+0x2a4/0x12f4
[ 108.040000] softirqs last enabled at (0): [<c001b768>] copy_process.part.2+0x2a4/0x12f4
[ 108.040000] softirqs last disabled at (0): [< (null)>] (null)
[ 108.040000] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G W 3.14.0-rc2-00004-g0db95f4 #128
[ 108.040000] [<c0014308>] (unwind_backtrace) from [<c0011690>] (show_stack+0x10/0x14)
[ 108.040000] [<c0011690>] (show_stack) from [<c03ae7d0>] (dump_stack+0x6c/0xb8)
[ 108.040000] [<c03ae7d0>] (dump_stack) from [<c00beed4>] (kmem_cache_alloc+0xd4/0x160)
[ 108.040000] [<c00beed4>] (kmem_cache_alloc) from [<c0068174>] (request_threaded_irq+0x64/0x130)
[ 108.040000] [<c0068174>] (request_threaded_irq) from [<c02efaf8>] (exynos4_local_timer_setup+0xd0/0x124)
[ 108.040000] [<c02efaf8>] (exynos4_local_timer_setup) from [<c02efc34>] (exynos4_mct_cpu_notify+0x78/0xf0)
[ 108.040000] [<c02efc34>] (exynos4_mct_cpu_notify) from [<c003d318>] (notifier_call_chain+0x44/0x84)
[ 108.040000] [<c003d318>] (notifier_call_chain) from [<c001d61c>] (__cpu_notify+0x24/0x40)
[ 108.040000] [<c001d61c>] (__cpu_notify) from [<c0013314>] (secondary_start_kernel+0xe4/0x134)
[ 108.040000] [<c0013314>] (secondary_start_kernel) from [<40008624>] (0x40008624)

First patch fixes this problem by removing request_irq from exynos4_local_timer_setup
Second removes non-dt stuff.

Tested on linux kernel v3.14-rc2.
Comments and additions would be appreciated.
Thank you.
Tarek.

Tarek Dakhran (2):
clocksource: mct: remove request_irq from exynos4_local_timer_setup
clocksource: mct: cleanup, remove non-dt stuff from mct

arch/arm/mach-exynos/common.h | 2 --
drivers/clocksource/exynos_mct.c | 55 +++++++++++++++++++++-----------------
2 files changed, 31 insertions(+), 26 deletions(-)

--
1.7.10.4

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