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* [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference()
@ 2010-01-05  2:03 Paul E. McKenney
  2010-01-05  2:04 ` [PATCH tip/core/rcu 1/8] rcu: introduce lockdep-based checking to RCU read-side primitives Paul E. McKenney
                   ` (8 more replies)
  0 siblings, 9 replies; 21+ messages in thread
From: Paul E. McKenney @ 2010-01-05  2:03 UTC (permalink / raw)
  To: linux-kernel
  Cc: mingo, laijs, dipankar, akpm, mathieu.desnoyers, josh, dvhltc,
	niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells

Hello!

This patch series adds lockdep-based checking to the rcu_dereference()
primitive in order to flag misuses of RCU.  The first three patches
put the RCU infrastructure in place, while the last five use this
infrastructure in the net, sched, vfs, radix-tree, and idr subsystems.
There are very likely additional changes required.

							Thanx, Paul


 b/fs/file.c                     |    2 
 b/include/linux/cgroup.h        |    2 
 b/include/linux/cred.h          |    2 
 b/include/linux/fdtable.h       |    8 +-
 b/include/linux/rculist.h       |   14 ++--
 b/include/linux/rculist_nulls.h |    5 -
 b/include/linux/rcupdate.h      |  124 ++++++++++++++++++++++++++++++++++++----
 b/include/linux/srcu.h          |   87 +++++++++++++++++++++++++++-
 b/init/main.c                   |    2 
 b/kernel/exit.c                 |   14 +++-
 b/kernel/fork.c                 |    1 
 b/kernel/notifier.c             |    6 -
 b/kernel/pid.c                  |    2 
 b/kernel/rcupdate.c             |   10 +++
 b/kernel/rcutorture.c           |   12 +++
 b/kernel/sched.c                |    7 --
 b/kernel/srcu.c                 |   50 ++++++++++------
 b/lib/debug_locks.c             |    2 
 b/lib/idr.c                     |    9 +-
 b/lib/radix-tree.c              |   25 +++-----
 b/net/core/dev.c                |    2 
 b/net/core/filter.c             |    6 -
 b/net/core/sock.c               |    2 
 b/net/decnet/dn_route.c         |   14 ++--
 b/net/ipv4/route.c              |   14 ++--
 b/net/packet/af_packet.c        |    3 
 include/linux/rcupdate.h        |   45 ++++++++++----
 include/linux/srcu.h            |    9 ++
 28 files changed, 369 insertions(+), 110 deletions(-)

^ permalink raw reply	[flat|nested] 21+ messages in thread
* [PATCH tip/core/rcu 08/21] vfs: apply lockdep-based checking to rcu_dereference() uses
@ 2010-02-23  1:04 Paul E. McKenney
  2010-02-25 10:11 ` [tip:core/rcu] vfs: Apply " tip-bot for Paul E. McKenney
  0 siblings, 1 reply; 21+ messages in thread
From: Paul E. McKenney @ 2010-02-23  1:04 UTC (permalink / raw)
  To: linux-kernel
  Cc: mingo, laijs, dipankar, akpm, mathieu.desnoyers, josh, dvhltc,
	niv, tglx, peterz, rostedt, Valdis.Kletnieks, dhowells,
	Paul E. McKenney, Alexander Viro

Add lockdep-ified RCU primitives to alloc_fd(), files_fdtable() and
fcheck_files().

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 fs/file.c               |    2 +-
 fs/proc/array.c         |    2 ++
 fs/proc/base.c          |    6 +++++-
 include/linux/fdtable.h |    8 ++++++--
 4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/file.c b/fs/file.c
index 87e1290..38039af 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -478,7 +478,7 @@ repeat:
 	error = fd;
 #if 1
 	/* Sanity check */
-	if (rcu_dereference(fdt->fd[fd]) != NULL) {
+	if (rcu_dereference_raw(fdt->fd[fd]) != NULL) {
 		printk(KERN_WARNING "alloc_fd: slot %d not NULL!\n", fd);
 		rcu_assign_pointer(fdt->fd[fd], NULL);
 	}
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 13b5d07..18e20fe 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -270,7 +270,9 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p)
 		blocked = p->blocked;
 		collect_sigign_sigcatch(p, &ignored, &caught);
 		num_threads = atomic_read(&p->signal->count);
+		rcu_read_lock();  /* FIXME: is this correct? */
 		qsize = atomic_read(&__task_cred(p)->user->sigpending);
+		rcu_read_unlock();
 		qlim = p->signal->rlim[RLIMIT_SIGPENDING].rlim_cur;
 		unlock_task_sighand(p, &flags);
 	}
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 18d5cc6..db19ca8 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1095,8 +1095,12 @@ static ssize_t proc_loginuid_write(struct file * file, const char __user * buf,
 	if (!capable(CAP_AUDIT_CONTROL))
 		return -EPERM;
 
-	if (current != pid_task(proc_pid(inode), PIDTYPE_PID))
+	rcu_read_lock();
+	if (current != pid_task(proc_pid(inode), PIDTYPE_PID)) {
+		rcu_read_unlock();
 		return -EPERM;
+	}
+	rcu_read_unlock();
 
 	if (count >= PAGE_SIZE)
 		count = PAGE_SIZE - 1;
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index a2ec74b..144412f 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -57,7 +57,11 @@ struct files_struct {
 	struct file * fd_array[NR_OPEN_DEFAULT];
 };
 
-#define files_fdtable(files) (rcu_dereference((files)->fdt))
+#define files_fdtable(files) \
+	(rcu_dereference_check((files)->fdt, \
+			       rcu_read_lock_held() || \
+			       lockdep_is_held(&(files)->file_lock) || \
+			       atomic_read(&files->count) == 1))
 
 struct file_operations;
 struct vfsmount;
@@ -78,7 +82,7 @@ static inline struct file * fcheck_files(struct files_struct *files, unsigned in
 	struct fdtable *fdt = files_fdtable(files);
 
 	if (fd < fdt->max_fds)
-		file = rcu_dereference(fdt->fd[fd]);
+		file = rcu_dereference_check(fdt->fd[fd], rcu_read_lock_held() || lockdep_is_held(&files->file_lock) || atomic_read(&files->count) == 1);
 	return file;
 }
 
-- 
1.6.6


^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2010-02-25 10:12 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2010-01-05  2:03 [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference() Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 1/8] rcu: introduce lockdep-based checking to RCU read-side primitives Paul E. McKenney
2010-01-13 10:28   ` [tip:core/rcu] rcu: Introduce " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 2/8] rcu: add lockdep-enabled variants of rcu_dereference() Paul E. McKenney
2010-01-13 10:28   ` [tip:core/rcu] rcu: Add " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 3/8] rcu: disable lockdep checking in RCU list-traversal primitives Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] rcu: Disable " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 4/8] net: add checking to rcu_dereference() primitives Paul E. McKenney
2010-01-13 10:30   ` [tip:core/rcu] net: Add " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 5/8] sched: use lockdep-based checking on rcu_dereference() Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] sched: Use " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 6/8] vfs: apply lockdep-based checking to rcu_dereference() uses Paul E. McKenney
2010-01-13 10:30   ` [tip:core/rcu] vfs: Apply " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 7/8] radix-tree: disable RCU lockdep checking in radix tree Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] radix-tree: Disable " tip-bot for Paul E. McKenney
2010-01-05  2:04 ` [PATCH tip/core/rcu 8/8] idr: apply lockdep-based diagnostics to rcu_dereference() uses Paul E. McKenney
2010-01-13 10:29   ` [tip:core/rcu] idr: Apply " tip-bot for Paul E. McKenney
2010-01-13  9:22 ` [PATCH tip/core/rcu 0/8] rcu: add lockdep-based diagnostics to rcu_dereference() Ingo Molnar
2010-01-13 16:17   ` Paul E. McKenney
2010-01-13 16:37     ` Ingo Molnar
2010-02-23  1:04 [PATCH tip/core/rcu 08/21] vfs: apply lockdep-based checking to rcu_dereference() uses Paul E. McKenney
2010-02-25 10:11 ` [tip:core/rcu] vfs: Apply " tip-bot for Paul E. McKenney

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