From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH tip/core/rcu 6/9] vfs: apply lockdep-based checking to rcu_dereference() uses
Date: Thu, 14 Jan 2010 17:02:43 -0800 [thread overview]
Message-ID: <12635173662545-git-send-email-> (raw)
In-Reply-To: <20100115010157.GA28221@linux.vnet.ibm.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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;
}
--
1.5.2.5
next prev parent reply other threads:[~2010-01-15 1:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-15 1:01 [PATCH tip/core/rcu 0/9] rcu: v3 add lockdep-based diagnostics to rcu_dereference() Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 1/9] rcu: introduce lockdep-based checking to RCU read-side primitives Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 2/9] rcu: add lockdep-enabled variants of rcu_dereference() Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 3/9] rcu: disable lockdep checking in RCU list-traversal primitives Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 4/9] net: add checking to rcu_dereference() primitives Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 5/9] sched: use lockdep-based checking on rcu_dereference() Paul E. McKenney
2010-01-15 1:02 ` Paul E. McKenney [this message]
2010-01-15 1:02 ` [PATCH tip/core/rcu 7/9] radix-tree: disable RCU lockdep checking in radix tree Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 8/9] idr: apply lockdep-based diagnostics to rcu_dereference() uses Paul E. McKenney
2010-01-18 23:36 ` Josh Triplett
2010-01-19 0:56 ` Paul E. McKenney
2010-01-15 1:02 ` [PATCH tip/core/rcu 9/9] rcu: documentation update for CONFIG_PROVE_RCU Paul E. McKenney
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