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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2010-02-22 17:04:52 -0800
committerIngo Molnar <mingo@elte.hu>2010-02-25 10:34:48 +0100
commit7dc52157982ab771f40e3c0b7dc55b954c3c2d19 (patch)
treea41e39174d9535f0c678eb36249ceee4a1775d6b
parent497f0ab39cd25bed317b29482c147c967f7ecd1f (diff)
vfs: Apply lockdep-based checking to rcu_dereference() uses
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> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: Alexander Viro <viro@zeniv.linux.org.uk> LKML-Reference: <1266887105-1528-8-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--fs/file.c2
-rw-r--r--fs/proc/array.c2
-rw-r--r--fs/proc/base.c6
-rw-r--r--include/linux/fdtable.h8
4 files changed, 14 insertions, 4 deletions
diff --git a/fs/file.c b/fs/file.c
index 87e129030ab..38039af6766 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 13b5d070817..18e20feee25 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 58324c29916..623e2ffb5d2 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 a2ec74bc481..144412fface 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;
}