From 70ed91c6ec7f8bf20369634017d887d48ac979d2 Mon Sep 17 00:00:00 2001 From: "zhangwei(Jovi)" Date: Fri, 17 Jan 2014 17:08:38 +0900 Subject: [PATCH] tracing/uprobes: Support ftrace_event_file base multibuffer Support multi-buffer on uprobe-based dynamic events by using ftrace_event_file. This patch is based kprobe-based dynamic events multibuffer support work initially, commited by Masami(commit 41a7dd420c), but revised as below: Oleg changed the kprobe-based multibuffer design from array-pointers of ftrace_event_file into simple list, so this patch also change to the list design. rcu_read_lock/unlock added into uprobe_trace_func/uretprobe_trace_func, to synchronize with ftrace_event_file list add and delete. Even though we allow multi-uprobes instances now, but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive in probe_event_enable currently, this means we cannot allow one user is using uprobe-tracer, and another user is using perf-probe on same uprobe concurrently. (Perhaps this will be fix in future, kprobe don't have this limitation now) Link: http://lkml.kernel.org/r/1389946120-19610-4-git-send-email-namhyung@kernel.org Reviewed-by: Masami Hiramatsu Reviewed-by: Oleg Nesterov Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Srikar Dronamraju Signed-off-by: zhangwei(Jovi) Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/trace_kprobe.c | 17 ------ kernel/trace/trace_probe.h | 17 ++++++ kernel/trace/trace_uprobe.c | 105 ++++++++++++++++++++++++++++-------- 3 files changed, 101 insertions(+), 38 deletions(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index bdbae450c13e..d021d21dd150 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -35,11 +35,6 @@ struct trace_kprobe { struct trace_probe tp; }; -struct event_file_link { - struct ftrace_event_file *file; - struct list_head list; -}; - #define SIZEOF_TRACE_KPROBE(n) \ (offsetof(struct trace_kprobe, tp.args) + \ (sizeof(struct probe_arg) * (n))) @@ -387,18 +382,6 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file) return ret; } -static struct event_file_link * -find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file) -{ - struct event_file_link *link; - - list_for_each_entry(link, &tp->files, list) - if (link->file == file) - return link; - - return NULL; -} - /* * Disable trace_probe * if the file is NULL, disable "perf" handler, or disable "trace" handler. diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index b73574a5f429..fb1ab5dfbd42 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -288,6 +288,11 @@ struct trace_probe { struct probe_arg args[]; }; +struct event_file_link { + struct ftrace_event_file *file; + struct list_head list; +}; + static inline bool trace_probe_is_enabled(struct trace_probe *tp) { return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE)); @@ -316,6 +321,18 @@ static inline int is_good_name(const char *name) return 1; } +static inline struct event_file_link * +find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file) +{ + struct event_file_link *link; + + list_for_each_entry(link, &tp->files, list) + if (link->file == file) + return link; + + return NULL; +} + extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size, struct probe_arg *parg, bool is_return, bool is_kprobe); diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index d83155e0da78..349c6df9e332 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -260,6 +260,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret) goto error; INIT_LIST_HEAD(&tu->list); + INIT_LIST_HEAD(&tu->tp.files); tu->consumer.handler = uprobe_dispatcher; if (is_ret) tu->consumer.ret_handler = uretprobe_dispatcher; @@ -760,7 +761,8 @@ static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb) static void __uprobe_trace_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, - struct uprobe_cpu_buffer *ucb, int dsize) + struct uprobe_cpu_buffer *ucb, int dsize, + struct ftrace_event_file *ftrace_file) { struct uprobe_trace_entry_head *entry; struct ring_buffer_event *event; @@ -769,13 +771,15 @@ static void __uprobe_trace_func(struct trace_uprobe *tu, int size, esize; struct ftrace_event_call *call = &tu->tp.call; + WARN_ON(call != ftrace_file->event_call); + if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE)) return; esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu)); size = esize + tu->tp.size + dsize; - event = trace_current_buffer_lock_reserve(&buffer, call->event.type, - size, 0, 0); + event = trace_event_buffer_lock_reserve(&buffer, ftrace_file, + call->event.type, size, 0, 0); if (!event) return; @@ -799,8 +803,16 @@ static void __uprobe_trace_func(struct trace_uprobe *tu, static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { - if (!is_ret_probe(tu)) - __uprobe_trace_func(tu, 0, regs, ucb, dsize); + struct event_file_link *link; + + if (is_ret_probe(tu)) + return 0; + + rcu_read_lock(); + list_for_each_entry_rcu(link, &tu->tp.files, list) + __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file); + rcu_read_unlock(); + return 0; } @@ -808,7 +820,12 @@ static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func, struct pt_regs *regs, struct uprobe_cpu_buffer *ucb, int dsize) { - __uprobe_trace_func(tu, func, regs, ucb, dsize); + struct event_file_link *link; + + rcu_read_lock(); + list_for_each_entry_rcu(link, &tu->tp.files, list) + __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file); + rcu_read_unlock(); } /* Event entry printers */ @@ -855,12 +872,31 @@ typedef bool (*filter_func_t)(struct uprobe_consumer *self, struct mm_struct *mm); static int -probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter) +probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, + filter_func_t filter) { - int ret = 0; + bool enabled = trace_probe_is_enabled(&tu->tp); + struct event_file_link *link = NULL; + int ret; - if (trace_probe_is_enabled(&tu->tp)) - return -EINTR; + if (file) { + if (tu->tp.flags & TP_FLAG_PROFILE) + return -EINTR; + + link = kmalloc(sizeof(*link), GFP_KERNEL); + if (!link) + return -ENOMEM; + + link->file = file; + list_add_tail_rcu(&link->list, &tu->tp.files); + + tu->tp.flags |= TP_FLAG_TRACE; + } else { + if (tu->tp.flags & TP_FLAG_TRACE) + return -EINTR; + + tu->tp.flags |= TP_FLAG_PROFILE; + } ret = uprobe_buffer_enable(); if (ret < 0) @@ -868,24 +904,49 @@ probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter) WARN_ON(!uprobe_filter_is_empty(&tu->filter)); - tu->tp.flags |= flag; + if (enabled) + return 0; + tu->consumer.filter = filter; ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); - if (ret) - tu->tp.flags &= ~flag; + if (ret) { + if (file) { + list_del(&link->list); + kfree(link); + tu->tp.flags &= ~TP_FLAG_TRACE; + } else + tu->tp.flags &= ~TP_FLAG_PROFILE; + } return ret; } -static void probe_event_disable(struct trace_uprobe *tu, int flag) +static void +probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file) { if (!trace_probe_is_enabled(&tu->tp)) return; + if (file) { + struct event_file_link *link; + + link = find_event_file_link(&tu->tp, file); + if (!link) + return; + + list_del_rcu(&link->list); + /* synchronize with u{,ret}probe_trace_func */ + synchronize_sched(); + kfree(link); + + if (!list_empty(&tu->tp.files)) + return; + } + WARN_ON(!uprobe_filter_is_empty(&tu->filter)); uprobe_unregister(tu->inode, tu->offset, &tu->consumer); - tu->tp.flags &= ~flag; + tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; uprobe_buffer_disable(); } @@ -1077,25 +1138,27 @@ static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func, } #endif /* CONFIG_PERF_EVENTS */ -static -int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data) +static int +trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, + void *data) { struct trace_uprobe *tu = event->data; + struct ftrace_event_file *file = data; switch (type) { case TRACE_REG_REGISTER: - return probe_event_enable(tu, TP_FLAG_TRACE, NULL); + return probe_event_enable(tu, file, NULL); case TRACE_REG_UNREGISTER: - probe_event_disable(tu, TP_FLAG_TRACE); + probe_event_disable(tu, file); return 0; #ifdef CONFIG_PERF_EVENTS case TRACE_REG_PERF_REGISTER: - return probe_event_enable(tu, TP_FLAG_PROFILE, uprobe_perf_filter); + return probe_event_enable(tu, NULL, uprobe_perf_filter); case TRACE_REG_PERF_UNREGISTER: - probe_event_disable(tu, TP_FLAG_PROFILE); + probe_event_disable(tu, NULL); return 0; case TRACE_REG_PERF_OPEN: