1. Shift mutex_lock(event_mutex) from print/apply_event_filter to the callers. And rename them just in case.
2. Change the callers, event_filter_read() and event_filter_write() to read call = i_private under this mutex and abort if it is NULL. 3. Remove .open from ftrace_event_filter_fops. Note: I think event_filter_read() should not use "struct trace_seq". It buys nothing compared to the simple kmalloc'ed buffer, just needs a bit more memory and efforts. Signed-off-by: Oleg Nesterov <[email protected]> --- kernel/trace/trace.h | 4 ++-- kernel/trace/trace_events.c | 29 ++++++++++++++++++----------- kernel/trace/trace_events_filter.c | 21 ++++++++------------- 3 files changed, 28 insertions(+), 26 deletions(-) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4a4f6e1..57199ac 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -985,9 +985,9 @@ struct filter_pred { extern enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not); -extern void print_event_filter(struct ftrace_event_call *call, +extern void __print_event_filter(struct ftrace_event_call *call, struct trace_seq *s); -extern int apply_event_filter(struct ftrace_event_call *call, +extern int __apply_event_filter(struct ftrace_event_call *call, char *filter_string); extern int apply_subsystem_event_filter(struct ftrace_subsystem_dir *dir, char *filter_string); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 6401b51..f4a86f9 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -959,9 +959,9 @@ static ssize_t event_filter_read(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { - struct ftrace_event_call *call = filp->private_data; + struct ftrace_event_call *call; struct trace_seq *s; - int r; + int r = -ENODEV; if (*ppos) return 0; @@ -969,14 +969,18 @@ event_filter_read(struct file *filp, char __user *ubuf, size_t cnt, s = kmalloc(sizeof(*s), GFP_KERNEL); if (!s) return -ENOMEM; - trace_seq_init(s); - print_event_filter(call, s); - r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len); + mutex_lock(&event_mutex); + call = file_inode(filp)->i_private; + if (likely(call)) + __print_event_filter(call, s); + mutex_unlock(&event_mutex); - kfree(s); + if (call) + r = simple_read_from_buffer(ubuf, cnt, ppos, s->buffer, s->len); + kfree(s); return r; } @@ -984,9 +988,9 @@ static ssize_t event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) { - struct ftrace_event_call *call = filp->private_data; + struct ftrace_event_call *call; char *buf; - int err; + int err = -ENODEV; if (cnt >= PAGE_SIZE) return -EINVAL; @@ -1001,13 +1005,17 @@ event_filter_write(struct file *filp, const char __user *ubuf, size_t cnt, } buf[cnt] = '\0'; - err = apply_event_filter(call, buf); + mutex_lock(&event_mutex); + call = file_inode(filp)->i_private; + if (likely(call)) + err = __apply_event_filter(call, buf); + mutex_unlock(&event_mutex); + free_page((unsigned long) buf); if (err < 0) return err; *ppos += cnt; - return cnt; } @@ -1240,7 +1248,6 @@ static const struct file_operations ftrace_event_id_fops = { }; static const struct file_operations ftrace_event_filter_fops = { - .open = tracing_open_generic, .read = event_filter_read, .write = event_filter_write, .llseek = default_llseek, diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 0d883dc..f4b5eed 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -637,17 +637,15 @@ static void append_filter_err(struct filter_parse_state *ps, free_page((unsigned long) buf); } -void print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) +/* caller must hold event_mutex */ +void __print_event_filter(struct ftrace_event_call *call, struct trace_seq *s) { - struct event_filter *filter; + struct event_filter *filter = call->filter; - mutex_lock(&event_mutex); - filter = call->filter; if (filter && filter->filter_string) trace_seq_printf(s, "%s\n", filter->filter_string); else trace_seq_printf(s, "none\n"); - mutex_unlock(&event_mutex); } void print_subsystem_event_filter(struct event_subsystem *system, @@ -1841,23 +1839,22 @@ static int create_system_filter(struct event_subsystem *system, return err; } -int apply_event_filter(struct ftrace_event_call *call, char *filter_string) +/* caller must hold event_mutex */ +int __apply_event_filter(struct ftrace_event_call *call, char *filter_string) { struct event_filter *filter; int err = 0; - mutex_lock(&event_mutex); - if (!strcmp(strstrip(filter_string), "0")) { filter_disable(call); filter = call->filter; if (!filter) - goto out_unlock; + goto out; RCU_INIT_POINTER(call->filter, NULL); /* Make sure the filter is not being used */ synchronize_sched(); __free_filter(filter); - goto out_unlock; + goto out; } err = create_filter(call, filter_string, true, &filter); @@ -1884,9 +1881,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string) __free_filter(tmp); } } -out_unlock: - mutex_unlock(&event_mutex); - +out: return err; } -- 1.5.5.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
