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coresight-stm: fix list_add double add issue

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In race condition, when stm_source_link_add is called, the link
from stm_source to stm device has been established, src->Link_entry
has been added to STM->link_list, this is the root cause for this isse.
this change add a mutex lock to ensure that only one thread can enter
stm_source_link_store().

Change-Id: I8abf4275c590508f316a1337e604a4ed58563626
Signed-off-by: Yuanfang Zhang <quic_yuanfang@quicinc.com>
This commit is contained in:
Yuanfang Zhang 2022-04-01 18:07:21 +08:00 committed by Gerrit - the friendly Code Review server
parent cb5ed64bbf
commit c7d62ab557
2 changed files with 7 additions and 3 deletions
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9
drivers/hwtracing/stm/core.c
View File

@ -1171,12 +1171,14 @@ static ssize_t stm_source_link_store(struct device *dev,
struct stm_device *link;
int err;
mutex_lock(&src->link_mutex);
stm_source_link_drop(src);
link = stm_find_device(buf);
if (!link)
if (!link) {
mutex_unlock(&src->link_mutex);
return -EINVAL;
}
pm_runtime_get(&link->dev);
err = stm_source_link_add(src, link);
@ -1185,7 +1187,7 @@ static ssize_t stm_source_link_store(struct device *dev,
/* matches the stm_find_device() above */
stm_put_device(link);
}
mutex_unlock(&src->link_mutex);
return err ? : count;
}
@ -1251,6 +1253,7 @@ int stm_source_register_device(struct device *parent,
stm_output_init(&src->output);
spin_lock_init(&src->link_lock);
mutex_init(&src->link_mutex);
INIT_LIST_HEAD(&src->link_entry);
src->data = data;
data->src = src;

1
drivers/hwtracing/stm/stm.h
View File

@ -79,6 +79,7 @@ void stm_put_device(struct stm_device *stm);
struct stm_source_device {
struct device dev;
struct stm_source_data *data;
struct mutex link_mutex;
spinlock_t link_lock;
struct stm_device __rcu *link;
struct list_head link_entry;