linux/net/sunrpc/debugfs.c
Greg Kroah-Hartman ad6fef7769 rpc: properly check debugfs dentry before using it
debugfs can now report an error code if something went wrong instead of
just NULL.  So if the return value is to be used as a "real" dentry, it
needs to be checked if it is an error before dereferencing it.

This is now happening because of ff9fb72bc0 ("debugfs: return error
values, not NULL"), but why debugfs files are not being created properly
is an older issue, probably one that has always been there and should
probably be looked at...

Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <anna.schumaker@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
Reported-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
2019-02-12 15:51:39 -05:00

363 lines
7.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/**
* debugfs interface for sunrpc
*
* (c) 2014 Jeff Layton <jlayton@primarydata.com>
*/
#include <linux/debugfs.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/clnt.h>
#include "netns.h"
static struct dentry *topdir;
static struct dentry *rpc_fault_dir;
static struct dentry *rpc_clnt_dir;
static struct dentry *rpc_xprt_dir;
unsigned int rpc_inject_disconnect;
static int
tasks_show(struct seq_file *f, void *v)
{
u32 xid = 0;
struct rpc_task *task = v;
struct rpc_clnt *clnt = task->tk_client;
const char *rpc_waitq = "none";
if (RPC_IS_QUEUED(task))
rpc_waitq = rpc_qname(task->tk_waitqueue);
if (task->tk_rqstp)
xid = be32_to_cpu(task->tk_rqstp->rq_xid);
seq_printf(f, "%5u %04x %6d 0x%x 0x%x %8ld %ps %sv%u %s a:%ps q:%s\n",
task->tk_pid, task->tk_flags, task->tk_status,
clnt->cl_clid, xid, task->tk_timeout, task->tk_ops,
clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
task->tk_action, rpc_waitq);
return 0;
}
static void *
tasks_start(struct seq_file *f, loff_t *ppos)
__acquires(&clnt->cl_lock)
{
struct rpc_clnt *clnt = f->private;
loff_t pos = *ppos;
struct rpc_task *task;
spin_lock(&clnt->cl_lock);
list_for_each_entry(task, &clnt->cl_tasks, tk_task)
if (pos-- == 0)
return task;
return NULL;
}
static void *
tasks_next(struct seq_file *f, void *v, loff_t *pos)
{
struct rpc_clnt *clnt = f->private;
struct rpc_task *task = v;
struct list_head *next = task->tk_task.next;
++*pos;
/* If there's another task on list, return it */
if (next == &clnt->cl_tasks)
return NULL;
return list_entry(next, struct rpc_task, tk_task);
}
static void
tasks_stop(struct seq_file *f, void *v)
__releases(&clnt->cl_lock)
{
struct rpc_clnt *clnt = f->private;
spin_unlock(&clnt->cl_lock);
}
static const struct seq_operations tasks_seq_operations = {
.start = tasks_start,
.next = tasks_next,
.stop = tasks_stop,
.show = tasks_show,
};
static int tasks_open(struct inode *inode, struct file *filp)
{
int ret = seq_open(filp, &tasks_seq_operations);
if (!ret) {
struct seq_file *seq = filp->private_data;
struct rpc_clnt *clnt = seq->private = inode->i_private;
if (!atomic_inc_not_zero(&clnt->cl_count)) {
seq_release(inode, filp);
ret = -EINVAL;
}
}
return ret;
}
static int
tasks_release(struct inode *inode, struct file *filp)
{
struct seq_file *seq = filp->private_data;
struct rpc_clnt *clnt = seq->private;
rpc_release_client(clnt);
return seq_release(inode, filp);
}
static const struct file_operations tasks_fops = {
.owner = THIS_MODULE,
.open = tasks_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tasks_release,
};
void
rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
{
int len;
char name[24]; /* enough for "../../rpc_xprt/ + 8 hex digits + NULL */
struct rpc_xprt *xprt;
/* Already registered? */
if (clnt->cl_debugfs || !rpc_clnt_dir)
return;
len = snprintf(name, sizeof(name), "%x", clnt->cl_clid);
if (len >= sizeof(name))
return;
/* make the per-client dir */
clnt->cl_debugfs = debugfs_create_dir(name, rpc_clnt_dir);
if (!clnt->cl_debugfs)
return;
/* make tasks file */
if (!debugfs_create_file("tasks", S_IFREG | 0400, clnt->cl_debugfs,
clnt, &tasks_fops))
goto out_err;
rcu_read_lock();
xprt = rcu_dereference(clnt->cl_xprt);
/* no "debugfs" dentry? Don't bother with the symlink. */
if (IS_ERR_OR_NULL(xprt->debugfs)) {
rcu_read_unlock();
return;
}
len = snprintf(name, sizeof(name), "../../rpc_xprt/%s",
xprt->debugfs->d_name.name);
rcu_read_unlock();
if (len >= sizeof(name))
goto out_err;
if (!debugfs_create_symlink("xprt", clnt->cl_debugfs, name))
goto out_err;
return;
out_err:
debugfs_remove_recursive(clnt->cl_debugfs);
clnt->cl_debugfs = NULL;
}
void
rpc_clnt_debugfs_unregister(struct rpc_clnt *clnt)
{
debugfs_remove_recursive(clnt->cl_debugfs);
clnt->cl_debugfs = NULL;
}
static int
xprt_info_show(struct seq_file *f, void *v)
{
struct rpc_xprt *xprt = f->private;
seq_printf(f, "netid: %s\n", xprt->address_strings[RPC_DISPLAY_NETID]);
seq_printf(f, "addr: %s\n", xprt->address_strings[RPC_DISPLAY_ADDR]);
seq_printf(f, "port: %s\n", xprt->address_strings[RPC_DISPLAY_PORT]);
seq_printf(f, "state: 0x%lx\n", xprt->state);
return 0;
}
static int
xprt_info_open(struct inode *inode, struct file *filp)
{
int ret;
struct rpc_xprt *xprt = inode->i_private;
ret = single_open(filp, xprt_info_show, xprt);
if (!ret) {
if (!xprt_get(xprt)) {
single_release(inode, filp);
ret = -EINVAL;
}
}
return ret;
}
static int
xprt_info_release(struct inode *inode, struct file *filp)
{
struct rpc_xprt *xprt = inode->i_private;
xprt_put(xprt);
return single_release(inode, filp);
}
static const struct file_operations xprt_info_fops = {
.owner = THIS_MODULE,
.open = xprt_info_open,
.read = seq_read,
.llseek = seq_lseek,
.release = xprt_info_release,
};
void
rpc_xprt_debugfs_register(struct rpc_xprt *xprt)
{
int len, id;
static atomic_t cur_id;
char name[9]; /* 8 hex digits + NULL term */
if (!rpc_xprt_dir)
return;
id = (unsigned int)atomic_inc_return(&cur_id);
len = snprintf(name, sizeof(name), "%x", id);
if (len >= sizeof(name))
return;
/* make the per-client dir */
xprt->debugfs = debugfs_create_dir(name, rpc_xprt_dir);
if (!xprt->debugfs)
return;
/* make tasks file */
if (!debugfs_create_file("info", S_IFREG | 0400, xprt->debugfs,
xprt, &xprt_info_fops)) {
debugfs_remove_recursive(xprt->debugfs);
xprt->debugfs = NULL;
}
atomic_set(&xprt->inject_disconnect, rpc_inject_disconnect);
}
void
rpc_xprt_debugfs_unregister(struct rpc_xprt *xprt)
{
debugfs_remove_recursive(xprt->debugfs);
xprt->debugfs = NULL;
}
static int
fault_open(struct inode *inode, struct file *filp)
{
filp->private_data = kmalloc(128, GFP_KERNEL);
if (!filp->private_data)
return -ENOMEM;
return 0;
}
static int
fault_release(struct inode *inode, struct file *filp)
{
kfree(filp->private_data);
return 0;
}
static ssize_t
fault_disconnect_read(struct file *filp, char __user *user_buf,
size_t len, loff_t *offset)
{
char *buffer = (char *)filp->private_data;
size_t size;
size = sprintf(buffer, "%u\n", rpc_inject_disconnect);
return simple_read_from_buffer(user_buf, len, offset, buffer, size);
}
static ssize_t
fault_disconnect_write(struct file *filp, const char __user *user_buf,
size_t len, loff_t *offset)
{
char buffer[16];
if (len >= sizeof(buffer))
len = sizeof(buffer) - 1;
if (copy_from_user(buffer, user_buf, len))
return -EFAULT;
buffer[len] = '\0';
if (kstrtouint(buffer, 10, &rpc_inject_disconnect))
return -EINVAL;
return len;
}
static const struct file_operations fault_disconnect_fops = {
.owner = THIS_MODULE,
.open = fault_open,
.read = fault_disconnect_read,
.write = fault_disconnect_write,
.release = fault_release,
};
static struct dentry *
inject_fault_dir(struct dentry *topdir)
{
struct dentry *faultdir;
faultdir = debugfs_create_dir("inject_fault", topdir);
if (!faultdir)
return NULL;
if (!debugfs_create_file("disconnect", S_IFREG | 0400, faultdir,
NULL, &fault_disconnect_fops))
return NULL;
return faultdir;
}
void __exit
sunrpc_debugfs_exit(void)
{
debugfs_remove_recursive(topdir);
topdir = NULL;
rpc_fault_dir = NULL;
rpc_clnt_dir = NULL;
rpc_xprt_dir = NULL;
}
void __init
sunrpc_debugfs_init(void)
{
topdir = debugfs_create_dir("sunrpc", NULL);
if (!topdir)
return;
rpc_fault_dir = inject_fault_dir(topdir);
if (!rpc_fault_dir)
goto out_remove;
rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir);
if (!rpc_clnt_dir)
goto out_remove;
rpc_xprt_dir = debugfs_create_dir("rpc_xprt", topdir);
if (!rpc_xprt_dir)
goto out_remove;
return;
out_remove:
debugfs_remove_recursive(topdir);
topdir = NULL;
rpc_fault_dir = NULL;
rpc_clnt_dir = NULL;
}