[Linux-cachefs] [PATCH] Use proper lock in fscache_objlist_config.
Artem Savkov
asavkov at redhat.com
Tue Oct 4 13:38:30 UTC 2016
fscache_objlist_config doesn't hold rkey->sem when calling user_key_payload,
that can result in a "suspicious RCU usage" warning. It does hold
rcu_read_lock, so it either needs to use unprotected rcu_dereference,
or take rkey->sem instead of rcu_read_lock.
Signed-off-by: Artem Savkov <asavkov at redhat.com>
---
fs/fscache/object-list.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/fscache/object-list.c b/fs/fscache/object-list.c
index 5d5ddaa..26c20e9 100644
--- a/fs/fscache/object-list.c
+++ b/fs/fscache/object-list.c
@@ -327,7 +327,7 @@ static void fscache_objlist_config(struct fscache_objlist_data *data)
goto no_config;
config = 0;
- rcu_read_lock();
+ down_read(&key->sem);
confkey = user_key_payload(key);
buf = confkey->data;
@@ -349,7 +349,7 @@ static void fscache_objlist_config(struct fscache_objlist_data *data)
}
}
- rcu_read_unlock();
+ up_read(&key->sem);
key_put(key);
if (!(config & (FSCACHE_OBJLIST_CONFIG_COOKIE | FSCACHE_OBJLIST_CONFIG_NOCOOKIE)))
--
2.7.4
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