The patch titled
fix cpufreq_stats attrs removal
has been added to the -mm tree. Its filename is
fix-cpufreq_stats-attrs-removal.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: fix cpufreq_stats attrs removal
From: Mattia Dongili <malattia@xxxxxxxx>
After modprobe/rmmod cpufreq/stats directory appears but doesn't get
removed.
There are other symptoms to this same bug:
1. unload p4-clockmod: /sys/.../cpu0/cpufreq is removed all together
2. load p4-clockmod: /sys/.../cpu0/cpufreq appears but no 'stats' subdir
(yes, cpufreq_stats is loaded)
3. rmmod cpufreq_stats: Ooops!
Call Trace:
[<c0183f5b>] remove_dir+0x33/0xc4
[<c0184fca>] remove_files+0x1a/0x28
[<c018503b>] sysfs_remove_group+0x63/0x71
[<f898c38d>] cpufreq_stat_cpu_callback+0x51/0x8a [cpufreq_stats]
[<f898c477>] cpufreq_stats_exit+0x47/0x4b [cpufreq_stats]
[<c012f145>] sys_delete_module+0x190/0x1b7
[<c0140073>] do_wp_page+0x231/0x3e7
[<c0102e17>] syscall_call+0x7/0xb
The problem is cpufreq_stats doesn't know when a cpufreq driver is removed
and doesn't cleanup. I guess this affects any setup with cpufreq_stats.
The attached patch seems to solve both symptoms and yes... it's quite
invasive as it introduce one more cpufreq policy notification (REMOVED).
Cc: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/cpufreq/cpufreq.c | 4 ++++
drivers/cpufreq/cpufreq_stats.c | 26 +++++++++++++++-----------
include/linux/cpufreq.h | 1 +
3 files changed, 20 insertions(+), 11 deletions(-)
diff -puN drivers/cpufreq/cpufreq.c~fix-cpufreq_stats-attrs-removal drivers/cpufreq/cpufreq.c
--- a/drivers/cpufreq/cpufreq.c~fix-cpufreq_stats-attrs-removal
+++ a/drivers/cpufreq/cpufreq.c
@@ -989,6 +989,10 @@ static int __cpufreq_remove_dev (struct
unlock_policy_rwsem_write(cpu);
+ /* notify of policy cancellation */
+ blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
+ CPUFREQ_REMOVE, data);
+
kobject_unregister(&data->kobj);
kobject_put(&data->kobj);
diff -puN drivers/cpufreq/cpufreq_stats.c~fix-cpufreq_stats-attrs-removal drivers/cpufreq/cpufreq_stats.c
--- a/drivers/cpufreq/cpufreq_stats.c~fix-cpufreq_stats-attrs-removal
+++ a/drivers/cpufreq/cpufreq_stats.c
@@ -257,18 +257,23 @@ static int
cpufreq_stat_notifier_policy (struct notifier_block *nb, unsigned long val,
void *data)
{
- int ret;
+ int ret = 0;
struct cpufreq_policy *policy = data;
struct cpufreq_frequency_table *table;
unsigned int cpu = policy->cpu;
- if (val != CPUFREQ_NOTIFY)
- return 0;
- table = cpufreq_frequency_get_table(cpu);
- if (!table)
- return 0;
- if ((ret = cpufreq_stats_create_table(policy, table)))
- return ret;
- return 0;
+ switch (val) {
+ case CPUFREQ_NOTIFY:
+ table = cpufreq_frequency_get_table(cpu);
+ if (!table)
+ break;
+ ret = cpufreq_stats_create_table(policy, table);
+ break;
+
+ case CPUFREQ_REMOVE:
+ cpufreq_stats_free_table(cpu);
+ break;
+ }
+ return ret;
}
static int
@@ -371,8 +376,7 @@ __exit cpufreq_stats_exit(void)
CPUFREQ_TRANSITION_NOTIFIER);
unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
for_each_online_cpu(cpu) {
- cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier,
- CPU_DEAD, (void *)(long)cpu);
+ cpufreq_stats_free_table(cpu);
}
}
diff -puN include/linux/cpufreq.h~fix-cpufreq_stats-attrs-removal include/linux/cpufreq.h
--- a/include/linux/cpufreq.h~fix-cpufreq_stats-attrs-removal
+++ a/include/linux/cpufreq.h
@@ -96,6 +96,7 @@ struct cpufreq_policy {
#define CPUFREQ_ADJUST (0)
#define CPUFREQ_INCOMPATIBLE (1)
#define CPUFREQ_NOTIFY (2)
+#define CPUFREQ_REMOVE (3)
#define CPUFREQ_SHARED_TYPE_NONE (0) /* None */
#define CPUFREQ_SHARED_TYPE_HW (1) /* HW does needed coordination */
_
Patches currently in -mm which might be from malattia@xxxxxxxx are
git-acpi.patch
fix-cpufreq_stats-attrs-removal.patch
-
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