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Viresh Kumar 955ef48335 cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT 
With the rwsem lock around
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT), we
get circular dependency when we call sysfs_remove_group().

 ======================================================
 [ INFO: possible circular locking dependency detected ]
 3.9.0-rc7+ #15 Not tainted
 -------------------------------------------------------
 cat/2387 is trying to acquire lock:
  (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [<c02f6179>] lock_policy_rwsem_read+0x25/0x34

 but task is already holding lock:
  (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

-> #1 (s_active#41){++++.+}:
        [<c0055a79>] lock_acquire+0x61/0xbc
        [<c00fabf1>] sysfs_addrm_finish+0xc1/0x128
        [<c00f9819>] sysfs_hash_and_remove+0x35/0x64
        [<c00fbe6f>] remove_files.isra.0+0x1b/0x24
        [<c00fbea5>] sysfs_remove_group+0x2d/0xa8
        [<c02f9a0b>] cpufreq_governor_interactive+0x13b/0x35c
        [<c02f61df>] __cpufreq_governor+0x2b/0x8c
        [<c02f6579>] __cpufreq_set_policy+0xa9/0xf8
        [<c02f6b75>] store_scaling_governor+0x61/0x100
        [<c02f6f4d>] store+0x39/0x60
        [<c00f9b81>] sysfs_write_file+0xed/0x114
        [<c00b3fd1>] vfs_write+0x65/0xd8
        [<c00b424b>] sys_write+0x2f/0x50
        [<c000cdc1>] ret_fast_syscall+0x1/0x52

-> #0 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}:
        [<c0055253>] __lock_acquire+0xef3/0x13dc
        [<c0055a79>] lock_acquire+0x61/0xbc
        [<c03ee1f5>] down_read+0x25/0x30
        [<c02f6179>] lock_policy_rwsem_read+0x25/0x34
        [<c02f6edd>] show+0x21/0x58
        [<c00f9c0f>] sysfs_read_file+0x67/0xcc
        [<c00b40a7>] vfs_read+0x63/0xd8
        [<c00b41fb>] sys_read+0x2f/0x50
        [<c000cdc1>] ret_fast_syscall+0x1/0x52

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(s_active#41);
                                lock(&per_cpu(cpu_policy_rwsem, cpu));
                                lock(s_active#41);
   lock(&per_cpu(cpu_policy_rwsem, cpu));

  *** DEADLOCK ***

 2 locks held by cat/2387:
  #0:  (&buffer->mutex){+.+.+.}, at: [<c00f9bcd>] sysfs_read_file+0x25/0xcc
  #1:  (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc

 stack backtrace:
 [<c0011d55>] (unwind_backtrace+0x1/0x9c) from [<c03e9a09>] (print_circular_bug+0x19d/0x1e8)
 [<c03e9a09>] (print_circular_bug+0x19d/0x1e8) from [<c0055253>] (__lock_acquire+0xef3/0x13dc)
 [<c0055253>] (__lock_acquire+0xef3/0x13dc) from [<c0055a79>] (lock_acquire+0x61/0xbc)
 [<c0055a79>] (lock_acquire+0x61/0xbc) from [<c03ee1f5>] (down_read+0x25/0x30)
 [<c03ee1f5>] (down_read+0x25/0x30) from [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34)
 [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34) from [<c02f6edd>] (show+0x21/0x58)
 [<c02f6edd>] (show+0x21/0x58) from [<c00f9c0f>] (sysfs_read_file+0x67/0xcc)
 [<c00f9c0f>] (sysfs_read_file+0x67/0xcc) from [<c00b40a7>] (vfs_read+0x63/0xd8)
 [<c00b40a7>] (vfs_read+0x63/0xd8) from [<c00b41fb>] (sys_read+0x2f/0x50)
 [<c00b41fb>] (sys_read+0x2f/0x50) from [<c000cdc1>] (ret_fast_syscall+0x1/0x52)

This lock isn't required while calling __cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT). Remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-22 00:23:54 +02:00
..
acpi-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
amd_freq_sensitivity.c cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor 2013-04-10 13:19:26 +02:00
arm_big_little.c cpufreq: ARM big LITTLE: Improve print message 2013-05-12 14:04:15 +02:00
arm_big_little.h cpufreq: ARM big LITTLE: Move cpu_to_cluster() to arm_big_little.h 2013-05-12 14:04:15 +02:00
arm_big_little_dt.c cpufreq: ARM big LITTLE DT: Return CPUFREQ_ETERNAL if clock-latency isn't found 2013-05-12 14:04:15 +02:00
at32ap-cpufreq.c cpufreq: AVR32: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
blackfin-cpufreq.c cpufreq: blackfin: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
cpufreq-cpu0.c cpufreq: cpufreq-cpu0: Free parent node for error cases 2013-05-12 14:04:16 +02:00
cpufreq-nforce2.c cpufreq: drivers: Remove unnecessary assignments of policy-> members 2013-04-02 15:26:32 +02:00
cpufreq.c cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT 2013-05-22 00:23:54 +02:00
cpufreq_conservative.c cpufreq: conservative: Use an inline function to evaluate freq_target 2013-04-01 01:11:36 +02:00
cpufreq_governor.c cpufreq: governors: Fix CPUFREQ_GOV_POLICY_{INIT|EXIT} notifiers 2013-05-12 14:04:16 +02:00
cpufreq_governor.h cpufreq: governors: Fix CPUFREQ_GOV_POLICY_{INIT|EXIT} notifiers 2013-05-12 14:04:16 +02:00
cpufreq_ondemand.c cpufreq, ondemand: Remove leftover debug line 2013-05-13 14:02:31 +02:00
cpufreq_performance.c cpufreq: Improve debug prints 2012-11-15 00:33:06 +01:00
cpufreq_powersave.c cpufreq: Improve debug prints 2012-11-15 00:33:06 +01:00
cpufreq_stats.c cpufreq: Preserve sysfs files across suspend/resume 2013-05-15 21:47:17 +02:00
cpufreq_userspace.c cpufreq: Don't check cpu_online(policy->cpu) 2013-02-09 01:18:34 +01:00
cris-artpec3-cpufreq.c cpufreq: cris: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
cris-etraxfs-cpufreq.c cpufreq: cris: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
davinci-cpufreq.c cpufreq: davinci: move cpufreq driver to drivers/cpufreq 2013-04-08 13:02:31 +02:00
dbx500-cpufreq.c cpufreq: dbx500: Round to closest available freq 2013-04-11 23:23:57 +02:00
e_powersaver.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
elanfreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
exynos-cpufreq.c cpufreq: exynos: Remove error return even if no soc is found 2013-04-10 13:19:26 +02:00
exynos-cpufreq.h arm-soc: cleanups 2013-02-21 14:58:40 -08:00
exynos4x12-cpufreq.c arm-soc: cleanups 2013-02-21 14:58:40 -08:00
exynos4210-cpufreq.c arm-soc: cleanups 2013-02-21 14:58:40 -08:00
exynos5250-cpufreq.c arm-soc: cleanups 2013-02-21 14:58:40 -08:00
exynos5440-cpufreq.c cpufreq: exynos5440: Protect OPP search calls with RCU lock 2013-04-22 00:24:37 +02:00
freq_table.c cpufreq: Don't check cpu_online(policy->cpu) 2013-02-09 01:18:34 +01:00
gx-suspmod.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
highbank-cpufreq.c cpufreq: highbank: do not initialize array with a loop 2013-03-04 14:23:11 +01:00
ia64-acpi-cpufreq.c cpufreq: ia64: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
imx6q-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
integrator-cpufreq.c cpufreq: integrator: move cpufreq driver to drivers/cpufreq 2013-04-08 13:02:31 +02:00
intel_pstate.c cpufreq / intel_pstate: use vzalloc() instead of vmalloc()/memset(0) 2013-05-14 01:39:28 +02:00
Kconfig cpufreq: Fix incorrect dependecies for ARM SA11xx drivers 2013-05-12 14:04:16 +02:00
Kconfig.arm cpufreq: ARM big LITTLE: Fix Kconfig entries 2013-05-12 14:04:16 +02:00
Kconfig.powerpc cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
Kconfig.x86 cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor 2013-04-10 13:19:26 +02:00
kirkwood-cpufreq.c cpufreq / kirkwood: don't check resource with devm_ioremap_resource 2013-05-12 14:04:17 +02:00
longhaul.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
longhaul.h sections: fix section conflicts in drivers/cpufreq 2012-09-14 21:10:46 +02:00
longrun.c cpufreq: Add support for x86 cpuinfo auto loading v4 2012-01-26 16:49:06 -08:00
loongson2_cpufreq.c cpufreq: mips: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
Makefile cpufreq: exynos: Add cpufreq driver for exynos5440 2013-04-10 13:19:26 +02:00
maple-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
mperf.c [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
mperf.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
omap-cpufreq.c cpufreq: OMAP: instantiate omap-cpufreq as a platform_driver 2013-04-10 13:41:00 +02:00
p4-clockmod.c cpufreq: Don't check if cpu is online/offline for cpufreq callbacks 2013-04-02 15:26:32 +02:00
pcc-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
powernow-k6.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
powernow-k7.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
powernow-k7.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
powernow-k8.c cpufreq: Don't check if cpu is online/offline for cpufreq callbacks 2013-04-02 15:26:32 +02:00
powernow-k8.h cpufreq: Remove support for hardware P-state chips from powernow-k8 2012-09-09 22:05:30 +02:00
ppc_cbe_cpufreq.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq.h cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq_pervasive.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq_pmi.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
pxa2xx-cpufreq.c cpufreq: pxa2xx: initialize variables 2013-04-25 20:11:14 +02:00
pxa3xx-cpufreq.c cpufreq: pxa3xx: move cpufreq driver to drivers/cpufreq 2013-04-08 13:02:31 +02:00
s3c64xx-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
s3c2416-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
s5pv210-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
sa1100-cpufreq.c cpufreq: sa11x0: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:24 +02:00
sa1110-cpufreq.c cpufreq: sa11x0: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:24 +02:00
sc520_freq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
sh-cpufreq.c cpufreq: sh: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:25 +02:00
sparc-us2e-cpufreq.c cpufreq: sparc: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
sparc-us3-cpufreq.c cpufreq: sparc: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
spear-cpufreq.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
speedstep-centrino.c cpufreq: Don't check if cpu is online/offline for cpufreq callbacks 2013-04-02 15:26:32 +02:00
speedstep-ich.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
speedstep-lib.c cpufreq: Add support for x86 cpuinfo auto loading v4 2012-01-26 16:49:06 -08:00
speedstep-lib.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
speedstep-smi.c cpufreq: Notify all policy->cpus in cpufreq_notify_transition() 2013-04-02 15:24:00 +02:00
tegra-cpufreq.c cpufreq: tegra: Move driver to drivers/cpufreq 2013-04-08 13:02:30 +02:00
unicore2-cpufreq.c cpufreq: unicore2: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00