[PATCH 11/16] seccomp: Replace smp_read_barrier_depends() with lockless_dereference()

From: Pranith Kumar
Date: Thu Nov 13 2014 - 14:27:16 EST


Recently lockless_dereference() was added which can be used in place of
hard-coding smp_read_barrier_depends(). The following PATCH makes the change.

Signed-off-by: Pranith Kumar <bobby.prani@xxxxxxxxx>
---
kernel/seccomp.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 4ef9687..3729b06 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -175,17 +175,16 @@ static int seccomp_check_filter(struct sock_filter *filter, unsigned int flen)
*/
static u32 seccomp_run_filters(struct seccomp_data *sd)
{
- struct seccomp_filter *f = ACCESS_ONCE(current->seccomp.filter);
struct seccomp_data sd_local;
u32 ret = SECCOMP_RET_ALLOW;
+ /* Make sure cross-thread synced filter points somewhere sane. */
+ struct seccomp_filter *f =
+ lockless_dereference(current->seccomp.filter);

/* Ensure unexpected behavior doesn't result in failing open. */
if (unlikely(WARN_ON(f == NULL)))
return SECCOMP_RET_KILL;

- /* Make sure cross-thread synced filter points somewhere sane. */
- smp_read_barrier_depends();
-
if (!sd) {
populate_seccomp_data(&sd_local);
sd = &sd_local;
--
1.9.1

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