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authorDavid Howells <dhowells@redhat.com>2008-11-14 10:39:19 +1100
committerJames Morris <jmorris@namei.org>2008-11-14 10:39:19 +1100
commitc69e8d9c01db2adc503464993c358901c9af9de4 (patch)
treebed94aaa9aeb7a7834d1c880f72b62a11a752c78 /kernel/tsacct.c
parent86a264abe542cfececb4df129bc45a0338d8cdb9 (diff)
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CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds. This means that it will be possible for the credentials of a task to be replaced without another task (a) requiring a full lock to read them, and (b) seeing deallocated memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'kernel/tsacct.c')
-rw-r--r--kernel/tsacct.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 6d1ed07bf31..2dc06ab3571 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -27,6 +27,7 @@
*/
void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
{
+ const struct cred *tcred;
struct timespec uptime, ts;
u64 ac_etime;
@@ -53,10 +54,11 @@ void bacct_add_tsk(struct taskstats *stats, struct task_struct *tsk)
stats->ac_flag |= AXSIG;
stats->ac_nice = task_nice(tsk);
stats->ac_sched = tsk->policy;
- stats->ac_uid = tsk->cred->uid;
- stats->ac_gid = tsk->cred->gid;
stats->ac_pid = tsk->pid;
rcu_read_lock();
+ tcred = __task_cred(tsk);
+ stats->ac_uid = tcred->uid;
+ stats->ac_gid = tcred->gid;
stats->ac_ppid = pid_alive(tsk) ?
rcu_dereference(tsk->real_parent)->tgid : 0;
rcu_read_unlock();