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Commit 7dc52157 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

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: default avatarPaul 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: default avatarIngo Molnar <mingo@elte.hu>
parent 497f0ab3

fs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -478,7 +478,7 @@ int alloc_fd(unsigned start, unsigned flags) 
	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);

	}

fs/proc/array.c

+2 −0
Original line number Diff line number Diff line
@@ -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);

	}

fs/proc/base.c

+5 −1
Original line number Diff line number Diff line
@@ -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;

include/linux/fdtable.h

+6 −2
Original line number Diff line number Diff line
@@ -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;

}