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From: Amol Grover <frextrite@gmail.com>
To: David Howells <dhowells@redhat.com>,
	Shakeel Butt <shakeelb@google.com>,
	James Morris <jamorris@linux.microsoft.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	Amol Grover <frextrite@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joel@joelfernandes.org>,
	"Paul E . McKenney" <paulmck@kernel.org>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: [Linux-kernel-mentees] [PATCH] cred: Use RCU primitives to access RCU pointers
Date: Tue, 28 Jan 2020 12:57:41 +0530	[thread overview]
Message-ID: <20200128072740.21272-1-frextrite@gmail.com> (raw)

task_struct.cred and task_struct.real_cred are annotated by __rcu,
hence use rcu_access_pointer to access them.

Fixes the following sparse errors:
kernel/cred.c:144:9: error: incompatible types in comparison expression
(different address spaces):
kernel/cred.c:144:9:    struct cred *
kernel/cred.c:144:9:    struct cred const [noderef] <asn:4> *
kernel/cred.c:145:9: error: incompatible types in comparison expression
(different address spaces):
kernel/cred.c:145:9:    struct cred *
kernel/cred.c:145:9:    struct cred const [noderef] <asn:4> *

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 kernel/cred.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cred.c b/kernel/cred.c
index 809a985b1793..3043c8e1544d 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -141,8 +141,8 @@ void __put_cred(struct cred *cred)
 	cred->magic = CRED_MAGIC_DEAD;
 	cred->put_addr = __builtin_return_address(0);
 #endif
-	BUG_ON(cred == current->cred);
-	BUG_ON(cred == current->real_cred);
+	BUG_ON(cred == rcu_access_pointer(current->cred));
+	BUG_ON(cred == rcu_access_pointer(current->real_cred));
 
 	if (cred->non_rcu)
 		put_cred_rcu(&cred->rcu);
-- 
2.24.1

_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

WARNING: multiple messages have this Message-ID (diff)
From: Amol Grover <frextrite@gmail.com>
To: David Howells <dhowells@redhat.com>,
	Shakeel Butt <shakeelb@google.com>,
	James Morris <jamorris@linux.microsoft.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Kees Cook <keescook@chromium.org>,
	Amol Grover <frextrite@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jann Horn <jannh@google.com>
Cc: linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Joel Fernandes <joel@joelfernandes.org>,
	Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>,
	"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH] cred: Use RCU primitives to access RCU pointers
Date: Tue, 28 Jan 2020 12:57:41 +0530	[thread overview]
Message-ID: <20200128072740.21272-1-frextrite@gmail.com> (raw)

task_struct.cred and task_struct.real_cred are annotated by __rcu,
hence use rcu_access_pointer to access them.

Fixes the following sparse errors:
kernel/cred.c:144:9: error: incompatible types in comparison expression
(different address spaces):
kernel/cred.c:144:9:    struct cred *
kernel/cred.c:144:9:    struct cred const [noderef] <asn:4> *
kernel/cred.c:145:9: error: incompatible types in comparison expression
(different address spaces):
kernel/cred.c:145:9:    struct cred *
kernel/cred.c:145:9:    struct cred const [noderef] <asn:4> *

Signed-off-by: Amol Grover <frextrite@gmail.com>
---
 kernel/cred.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cred.c b/kernel/cred.c
index 809a985b1793..3043c8e1544d 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -141,8 +141,8 @@ void __put_cred(struct cred *cred)
 	cred->magic = CRED_MAGIC_DEAD;
 	cred->put_addr = __builtin_return_address(0);
 #endif
-	BUG_ON(cred == current->cred);
-	BUG_ON(cred == current->real_cred);
+	BUG_ON(cred == rcu_access_pointer(current->cred));
+	BUG_ON(cred == rcu_access_pointer(current->real_cred));
 
 	if (cred->non_rcu)
 		put_cred_rcu(&cred->rcu);
-- 
2.24.1


             reply	other threads:[~2020-01-28  7:28 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-28  7:27 Amol Grover [this message]
2020-01-28  7:27 ` [PATCH] cred: Use RCU primitives to access RCU pointers Amol Grover
2020-01-28  9:30 ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-01-28  9:30   ` Jann Horn
2020-01-28 11:48   ` [Linux-kernel-mentees] " Oleg Nesterov
2020-01-28 11:48     ` Oleg Nesterov
2020-01-28 12:19     ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-01-28 12:19       ` Jann Horn
2020-01-28 12:38       ` [Linux-kernel-mentees] " Oleg Nesterov
2020-01-28 12:38         ` Oleg Nesterov
2020-01-28 17:04   ` [Linux-kernel-mentees] " Amol Grover
2020-01-28 17:04     ` Amol Grover
2020-01-28 19:09     ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-01-28 19:09       ` Jann Horn
2020-01-29  6:57       ` [Linux-kernel-mentees] " Amol Grover
2020-01-29  6:57         ` Amol Grover
2020-01-29 14:14         ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-01-29 14:14           ` Jann Horn
2020-02-06  1:32           ` [Linux-kernel-mentees] " Joel Fernandes
2020-02-06  1:32             ` Joel Fernandes
2020-02-06 11:28             ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-02-06 11:28               ` Jann Horn
2020-02-06 16:49               ` [Linux-kernel-mentees] " Joel Fernandes
2020-02-06 16:49                 ` Joel Fernandes
2020-02-06 17:15                 ` [Linux-kernel-mentees] " Jann Horn via Linux-kernel-mentees
2020-02-06 17:15                   ` Jann Horn
2020-02-06 18:08                   ` [Linux-kernel-mentees] " Joel Fernandes
2020-02-06 18:08                     ` Joel Fernandes
2020-02-06 13:09             ` [Linux-kernel-mentees] " Amol Grover
2020-02-06 13:09               ` Amol Grover
2020-01-31 17:49   ` [Linux-kernel-mentees] " David Howells
2020-01-31 17:49     ` David Howells
2020-01-28 15:00 ` [Linux-kernel-mentees] " David Howells
2020-01-28 15:00   ` David Howells

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