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 --- tools/virtio/virtio-trace/trace-agent.h | 76 +++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) create mode 100644 tools/virtio/virtio-trace/trace-agent.h (limited to 'tools/virtio/virtio-trace/trace-agent.h') diff --git a/tools/virtio/virtio-trace/trace-agent.h b/tools/virtio/virtio-trace/trace-agent.h new file mode 100644 index 000000000..e67885969 --- /dev/null +++ b/tools/virtio/virtio-trace/trace-agent.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TRACE_AGENT_H__ +#define __TRACE_AGENT_H__ +#include +#include + +#define MAX_CPUS 256 +#define PIPE_INIT (1024*1024) + +/* + * agent_info - structure managing total information of guest agent + * @pipe_size: size of pipe (default 1MB) + * @use_stdout: set to true when o option is added (default false) + * @cpus: total number of CPUs + * @ctl_fd: fd of control path, /dev/virtio-ports/agent-ctl-path + * @rw_ti: structure managing information of read/write threads + */ +struct agent_info { + unsigned long pipe_size; + bool use_stdout; + int cpus; + int ctl_fd; + struct rw_thread_info *rw_ti[MAX_CPUS]; +}; + +/* + * rw_thread_info - structure managing a read/write thread a cpu + * @cpu_num: cpu number operating this read/write thread + * @in_fd: fd of reading trace data path in cpu_num + * @out_fd: fd of writing trace data path in cpu_num + * @read_pipe: fd of read pipe + * @write_pipe: fd of write pipe + * @pipe_size: size of pipe (default 1MB) + */ +struct rw_thread_info { + int cpu_num; + int in_fd; + int out_fd; + int read_pipe; + int write_pipe; + unsigned long pipe_size; +}; + +/* use for stopping rw threads */ +extern bool global_sig_receive; + +/* use for notification */ +extern bool global_run_operation; +extern pthread_mutex_t mutex_notify; +extern pthread_cond_t cond_wakeup; + +/* for controller of read/write threads */ +extern int rw_ctl_init(const char *ctl_path); +extern void *rw_ctl_loop(int ctl_fd); + +/* for trace read/write thread */ +extern void *rw_thread_info_new(void); +extern void *rw_thread_init(int cpu, const char *in_path, const char *out_path, + bool stdout_flag, unsigned long pipe_size, + struct rw_thread_info *rw_ti); +extern pthread_t rw_thread_run(struct rw_thread_info *rw_ti); + +static inline void *zalloc(size_t size) +{ + return calloc(1, size); +} + +#define pr_err(format, ...) fprintf(stderr, format, ## __VA_ARGS__) +#define pr_info(format, ...) fprintf(stdout, format, ## __VA_ARGS__) +#ifdef DEBUG +#define pr_debug(format, ...) fprintf(stderr, format, ## __VA_ARGS__) +#else +#define pr_debug(format, ...) do {} while (0) +#endif + +#endif /*__TRACE_AGENT_H__*/ -- cgit v1.3.1