[PATCH 1/4] oprofile: Handle initialisation failure more gracefully

Matt Fleming
2010-08-26T19:09:26Z

From: Will Deacon <will.deacon@arm.com>

The current implementation is not entirely safe in the case that
oprofile_arch_init() fails. We need to make sure that we always call
exit_driverfs() if we've called init_driverfs(). Also, avoid a potential
double free when freeing 'counter_config', e.g. don't free
'counter_config' in both oprofile_arch_init() and oprofile_arch_exit().

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm/oprofile/common.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/arm/oprofile/common.c b/arch/arm/oprofile/common.c
index 0691176..482779c 100644
--- a/arch/arm/oprofile/common.c
+++ b/arch/arm/oprofile/common.c
@@ -275,10 +275,12 @@ out:
return ret;
}

-static void exit_driverfs(void)
+static void exit_driverfs(void)
{
- platform_device_unregister(oprofile_pdev);
- platform_driver_unregister(&oprofile_driver);
+ if (!IS_ERR_OR_NULL(oprofile_pdev)) {
+ platform_device_unregister(oprofile_pdev);
+ platform_driver_unregister(&oprofile_driver);
+ }
}
#else
static int __init init_driverfs(void) { return 0; }
@@ -363,10 +365,8 @@ int __init oprofile_arch_init(struct oprofile_operations *ops)
}

ret = init_driverfs();
- if (ret) {
- kfree(counter_config);
+ if (ret)
return ret;
- }

for_each_possible_cpu(cpu) {
perf_events[cpu] = kcalloc(perf_num_counters,
@@ -401,8 +401,9 @@ void oprofile_arch_exit(void)
int cpu, id;
struct perf_event *event;

+ exit_driverfs();
+
if (*perf_events) {
- exit_driverfs();
for_each_possible_cpu(cpu) {
for (id = 0; id < perf_num_counters; ++id) {
event = perf_events[cpu][id];
--
1.7.1