[PATCH 2/5] uprobes: Introduce trace_uprobe->enabled

Oleg Nesterov
2013-01-28T18:26:19Z

probe_event_enable/disable() check tu->consumer != NULL to avoid
the wrong uprobe_register/unregister().

We are going to kill uprobe_trace_consumer, so we add the explicit
trace_uprobe->enabled member which can be used instead.

This is the temporary change to simplify the next patch, the new
member will go away after cleanups.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/trace/trace_uprobe.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index f49ccf9..c430d01 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -46,6 +46,7 @@ struct trace_uprobe {
struct list_head list;
struct ftrace_event_class class;
struct ftrace_event_call call;
+ bool enabled;
struct uprobe_trace_consumer *consumer;
struct trace_uprobe_filter filter;
struct inode *inode;
@@ -647,7 +648,7 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)
struct uprobe_trace_consumer *utc;
int ret = 0;

- if (tu->consumer)
+ if (tu->enabled)
return -EINTR;

utc = kzalloc(sizeof(struct uprobe_trace_consumer), GFP_KERNEL);
@@ -665,6 +666,8 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)
tu->consumer = NULL;
tu->flags &= ~flag;
kfree(utc);
+ } else {
+ tu->enabled = true;
}

return ret;
@@ -672,11 +675,12 @@ static int probe_event_enable(struct trace_uprobe *tu, int flag)

static void probe_event_disable(struct trace_uprobe *tu, int flag)
{
- if (!tu->consumer)
+ if (!tu->enabled)
return;

uprobe_unregister(tu->inode, tu->offset, &tu->consumer->cons);
tu->flags &= ~flag;
+ tu->enabled = false;
kfree(tu->consumer);
tu->consumer = NULL;
}
--
1.5.5.1