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/sysctl.c | 180 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 180 insertions(+) create mode 100644 net/sunrpc/sysctl.c (limited to 'net/sunrpc/sysctl.c') diff --git a/net/sunrpc/sysctl.c b/net/sunrpc/sysctl.c new file mode 100644 index 000000000..bdb587a72 --- /dev/null +++ b/net/sunrpc/sysctl.c @@ -0,0 +1,180 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/net/sunrpc/sysctl.c + * + * Sysctl interface to sunrpc module. + * + * I would prefer to register the sunrpc table below sys/net, but that's + * impossible at the moment. + */ + +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +#include "netns.h" + +/* + * Declare the debug flags here + */ +unsigned int rpc_debug; +EXPORT_SYMBOL_GPL(rpc_debug); + +unsigned int nfs_debug; +EXPORT_SYMBOL_GPL(nfs_debug); + +unsigned int nfsd_debug; +EXPORT_SYMBOL_GPL(nfsd_debug); + +unsigned int nlm_debug; +EXPORT_SYMBOL_GPL(nlm_debug); + +#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) + +static int proc_do_xprt(const struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + char tmpbuf[256]; + ssize_t len; + + if (write || *ppos) { + *lenp = 0; + return 0; + } + len = svc_print_xprts(tmpbuf, sizeof(tmpbuf)); + len = memory_read_from_buffer(buffer, *lenp, ppos, tmpbuf, len); + + if (len < 0) { + *lenp = 0; + return -EINVAL; + } + *lenp = len; + return 0; +} + +static int +proc_dodebug(const struct ctl_table *table, int write, void *buffer, size_t *lenp, + loff_t *ppos) +{ + char tmpbuf[20], *s = NULL; + char *p; + unsigned int value; + size_t left, len; + + if ((*ppos && !write) || !*lenp) { + *lenp = 0; + return 0; + } + + left = *lenp; + + if (write) { + p = buffer; + while (left && isspace(*p)) { + left--; + p++; + } + if (!left) + goto done; + + if (left > sizeof(tmpbuf) - 1) + return -EINVAL; + memcpy(tmpbuf, p, left); + tmpbuf[left] = '\0'; + + value = simple_strtol(tmpbuf, &s, 0); + if (s) { + left -= (s - tmpbuf); + if (left && !isspace(*s)) + return -EINVAL; + while (left && isspace(*s)) { + left--; + s++; + } + } else + left = 0; + *(unsigned int *) table->data = value; + /* Display the RPC tasks on writing to rpc_debug */ + if (strcmp(table->procname, "rpc_debug") == 0) + rpc_show_tasks(&init_net); + } else { + len = sprintf(tmpbuf, "0x%04x", *(unsigned int *) table->data); + if (len > left) + len = left; + memcpy(buffer, tmpbuf, len); + if ((left -= len) > 0) { + *((char *)buffer + len) = '\n'; + left--; + } + } + +done: + *lenp -= left; + *ppos += *lenp; + return 0; +} + +static struct ctl_table_header *sunrpc_table_header; + +static struct ctl_table debug_table[] = { + { + .procname = "rpc_debug", + .data = &rpc_debug, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dodebug + }, + { + .procname = "nfs_debug", + .data = &nfs_debug, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dodebug + }, + { + .procname = "nfsd_debug", + .data = &nfsd_debug, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dodebug + }, + { + .procname = "nlm_debug", + .data = &nlm_debug, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dodebug + }, + { + .procname = "transports", + .maxlen = 256, + .mode = 0444, + .proc_handler = proc_do_xprt, + }, +}; + +void +rpc_register_sysctl(void) +{ + if (!sunrpc_table_header) + sunrpc_table_header = register_sysctl("sunrpc", debug_table); +} + +void +rpc_unregister_sysctl(void) +{ + if (sunrpc_table_header) { + unregister_sysctl_table(sunrpc_table_header); + sunrpc_table_header = NULL; + } +} +#endif -- cgit v1.3.1