Re: [PATCH] kernel: audit.c: Add __rcu notation to RCU pointer
On Tue, Nov 26, 2019 at 10:57:23PM +0530, Amol Grover wrote:
add __rcu notation to RCU protected global pointer auditd_conn
Fixes multiple instances of sparse error:
error: incompatible types in comparison expression
(different address spaces)
Signed-off-by: Amol Grover <frextrite(a)gmail.com>
---
kernel/audit.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/audit.c b/kernel/audit.c
index da8dc0db5bd3..30e7fc9b8da2 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -102,12 +102,14 @@ struct audit_net {
* This struct is RCU protected; you must either hold the RCU lock for reading
* or the associated spinlock for writing.
*/
-static struct auditd_connection {
+struct auditd_connection {
struct pid *pid;
u32 portid;
struct net *net;
struct rcu_head rcu;
-} *auditd_conn = NULL;
+};
+static struct auditd_connection __rcu *auditd_conn;
+RCU_INIT_POINTER(auditd_conn);
Looks like this causes a build error. Always please build test your patches
in the very least. And I also did not understand how RCU_INIT_POINTER can
even be used outside of a function. In C, executable code cannot be outside
functions.
Is doing the following not sufficient to fix the sparse issue?
thanks,
- Joel
---8<-----------------------
diff --git a/kernel/audit.c b/kernel/audit.c
index 49b6049b26ac..c5d4b5a2dea1 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -108,8 +108,8 @@ struct auditd_connection {
struct net *net;
struct rcu_head rcu;
};
-static struct auditd_connection __rcu *auditd_conn;
-RCU_INIT_POINTER(auditd_conn);
+static struct auditd_connection __rcu *auditd_conn = NULL;
+
static DEFINE_SPINLOCK(auditd_conn_lock);
/* If audit_rate_limit is non-zero, limit the rate of sending audit records