From: Amol Grover <frextrite@gmail.com>
To: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
James Morris <jamorris@linux.microsoft.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Jann Horn <jannh@google.com>, David Howells <dhowells@redhat.com>,
Shakeel Butt <shakeelb@google.com>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paul Moore <paul@paul-moore.com>, Eric Paris <eparis@redhat.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
Amol Grover <frextrite@gmail.com>,
linux-kernel@vger.kernel.org,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
linux-audit@redhat.com, Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH 1/3 RESEND] sched: Remove __rcu annotation from cred pointer
Date: Thu, 2 Apr 2020 11:26:38 +0530 [thread overview]
Message-ID: <20200402055640.6677-1-frextrite@gmail.com> (raw)
task_struct::cred (subjective credentials) is *always* used
task-synchronously, hence, does not require RCU semantics.
task_struct::real_cred (objective credentials) can be used in
RCU context and its __rcu annotation is retained.
However, task_struct::cred and task_struct::real_cred *may*
point to the same object, hence, the object pointed to by
task_struct::cred *may* have RCU delayed freeing.
Suggested-by: Jann Horn <jannh@google.com>
Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
include/linux/sched.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 716ad1d8d95e..39924e6e0cf2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -879,8 +879,11 @@ struct task_struct {
/* Objective and real subjective task credentials (COW): */
const struct cred __rcu *real_cred;
- /* Effective (overridable) subjective task credentials (COW): */
- const struct cred __rcu *cred;
+ /*
+ * Effective (overridable) subjective task credentials (COW)
+ * which is used task-synchronously
+ */
+ const struct cred *cred;
#ifdef CONFIG_KEYS
/* Cached requested key. */
--
2.24.1
--
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next reply other threads:[~2020-04-02 13:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-02 5:56 Amol Grover [this message]
2020-04-02 5:56 ` [PATCH 2/3 RESEND] cred: Do not use RCU primitives to access cred pointer Amol Grover
2020-04-02 5:56 ` [PATCH 3/3 RESEND] auditsc: Do not use RCU primitive to read from " Amol Grover
2020-04-02 12:56 ` Paul Moore
2020-04-03 7:56 ` Amol Grover
2020-04-03 19:25 ` Paul Moore
2020-04-03 21:21 ` Richard Guy Briggs
2020-04-03 21:43 ` Paul Moore
2020-04-04 2:53 ` Richard Guy Briggs
2020-05-24 8:11 ` [PATCH 1/3 RESEND] sched: Remove __rcu annotation " Amol Grover
2020-05-25 13:17 ` Richard Guy Briggs
2020-05-25 18:04 ` Amol Grover
2020-05-26 12:34 ` Paul Moore
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