From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- net/sunrpc/debugfs.c | 309 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 309 insertions(+) create mode 100644 net/sunrpc/debugfs.c (limited to 'net/sunrpc/debugfs.c') diff --git a/net/sunrpc/debugfs.c b/net/sunrpc/debugfs.c new file mode 100644 index 000000000..32417db34 --- /dev/null +++ b/net/sunrpc/debugfs.c @@ -0,0 +1,309 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * debugfs interface for sunrpc + * + * (c) 2014 Jeff Layton + */ + +#include +#include +#include + +#include "netns.h" +#include "fail.h" + +static struct dentry *topdir; +static struct dentry *rpc_clnt_dir; +static struct dentry *rpc_xprt_dir; + +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, rpc_task_timeout(task), 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); + seq_printf(f, "clnt[%pISpc] RPC tasks[%d]\n", + (struct sockaddr *)&clnt->cl_xprt->addr, + atomic_read(&clnt->cl_task_count)); +} + +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 (!refcount_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, +}; + +static int do_xprt_debugfs(struct rpc_clnt *clnt, struct rpc_xprt *xprt, void *numv) +{ + int len; + char name[24]; /* enough for "../../rpc_xprt/ + 8 hex digits + NULL */ + char link[9]; /* enough for 8 hex digits + NULL */ + int *nump = numv; + + if (IS_ERR_OR_NULL(xprt->debugfs)) + return 0; + len = snprintf(name, sizeof(name), "../../rpc_xprt/%s", + xprt->debugfs->d_name.name); + if (len >= sizeof(name)) + return -1; + if (*nump == 0) + strcpy(link, "xprt"); + else { + len = snprintf(link, sizeof(link), "xprt%d", *nump); + if (len >= sizeof(link)) + return -1; + } + debugfs_create_symlink(link, clnt->cl_debugfs, name); + (*nump)++; + return 0; +} + +void +rpc_clnt_debugfs_register(struct rpc_clnt *clnt) +{ + int len; + char name[9]; /* enough for 8 hex digits + NULL */ + int xprtnum = 0; + + 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); + + /* make tasks file */ + debugfs_create_file("tasks", S_IFREG | 0400, clnt->cl_debugfs, clnt, + &tasks_fops); + + rpc_clnt_iterate_for_each_xprt(clnt, do_xprt_debugfs, &xprtnum); +} + +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); + seq_printf(f, "netns: %u\n", xprt->xprt_net->ns.inum); + + if (xprt->ops->get_srcaddr) { + int ret, buflen; + char buf[INET6_ADDRSTRLEN]; + + buflen = ARRAY_SIZE(buf); + ret = xprt->ops->get_srcaddr(xprt, buf, buflen); + if (ret < 0) + ret = sprintf(buf, ""); + seq_printf(f, "saddr: %.*s\n", ret, buf); + } + 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 */ + + 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); + + /* make tasks file */ + debugfs_create_file("info", S_IFREG | 0400, xprt->debugfs, xprt, + &xprt_info_fops); +} + +void +rpc_xprt_debugfs_unregister(struct rpc_xprt *xprt) +{ + debugfs_remove_recursive(xprt->debugfs); + xprt->debugfs = NULL; +} + +#if IS_ENABLED(CONFIG_FAIL_SUNRPC) +struct fail_sunrpc_attr fail_sunrpc = { + .attr = FAULT_ATTR_INITIALIZER, +}; +EXPORT_SYMBOL_GPL(fail_sunrpc); + +static void fail_sunrpc_init(void) +{ + struct dentry *dir; + + dir = fault_create_debugfs_attr("fail_sunrpc", NULL, + &fail_sunrpc.attr); + + debugfs_create_bool("ignore-client-disconnect", S_IFREG | 0600, dir, + &fail_sunrpc.ignore_client_disconnect); + + debugfs_create_bool("ignore-server-disconnect", S_IFREG | 0600, dir, + &fail_sunrpc.ignore_server_disconnect); + + debugfs_create_bool("ignore-cache-wait", S_IFREG | 0600, dir, + &fail_sunrpc.ignore_cache_wait); +} +#else +static void fail_sunrpc_init(void) +{ +} +#endif + +void __exit +sunrpc_debugfs_exit(void) +{ + debugfs_remove_recursive(topdir); + topdir = NULL; + rpc_clnt_dir = NULL; + rpc_xprt_dir = NULL; +} + +void __init +sunrpc_debugfs_init(void) +{ + topdir = debugfs_create_dir("sunrpc", NULL); + + rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir); + + rpc_xprt_dir = debugfs_create_dir("rpc_xprt", topdir); + + fail_sunrpc_init(); +} -- cgit v1.3.1