Messages in this thread Patch in this message | | | Date | Tue, 25 Jun 2013 16:16:13 +0800 | From | "zhangwei(Jovi)" <> | Subject | [PATCH 2/2] tracing/uprobes: disallow unregister trace_uprobe when trace_uprobe is in use |
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We cannot unregister trace_uprobe when trace_uprobe is in use, otherwise resource will leak.
Just return -EBUSY if user want to unregister a trace_uprobe which in use.
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> --- kernel/trace/trace_uprobe.c | 51 ++++++++++++++++++++++++++++++++----------- 1 file changed, 38 insertions(+), 13 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index d2da3ea..248757b 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -102,6 +102,11 @@ static inline bool is_ret_probe(struct trace_uprobe *tu) return tu->consumer.ret_handler != NULL; }
+static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu) +{ + return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE); +} + /* * Allocate new trace_uprobe and initialize it (including uprobes). */ @@ -171,11 +176,17 @@ static struct trace_uprobe *find_probe_event(const char *event, const char *grou }
/* Unregister a trace_uprobe and probe_event: call with locking uprobe_lock */ -static void unregister_trace_uprobe(struct trace_uprobe *tu) +static int unregister_trace_uprobe(struct trace_uprobe *tu) { + /* Enabled event can not be unregistered */ + if (is_trace_uprobe_enabled(tu)) + return -EBUSY; + list_del(&tu->list); unregister_uprobe_event(tu); free_trace_uprobe(tu); + + return 0; }
/* Register a trace_uprobe and probe_event */ @@ -188,9 +199,12 @@ static int register_trace_uprobe(struct trace_uprobe *tu)
/* register as an event */ old_tp = find_probe_event(tu->call.name, tu->call.class->system); - if (old_tp) + if (old_tp) { /* delete old event */ - unregister_trace_uprobe(old_tp); + ret = unregister_trace_uprobe(old_tp); + if (ret < 0) + goto end; + }
ret = register_uprobe_event(tu); if (ret) { @@ -276,9 +290,9 @@ static int create_trace_uprobe(int argc, char **argv) return -ENOENT; } /* delete an event */ - unregister_trace_uprobe(tu); + ret = unregister_trace_uprobe(tu); mutex_unlock(&uprobe_lock); - return 0; + return ret; }
if (argc < 2) { @@ -413,16 +427,27 @@ fail_address_parse: return ret; }
-static void cleanup_all_probes(void) +static int cleanup_all_probes(void) { struct trace_uprobe *tu; + int ret = 0;
mutex_lock(&uprobe_lock); + + /* Ensure no probe is in use. */ + list_for_each_entry(tu, &uprobe_list, list) + if (is_trace_uprobe_enabled(tu)) { + ret = -EBUSY; + goto end; + } + while (!list_empty(&uprobe_list)) { tu = list_entry(uprobe_list.next, struct trace_uprobe, list); unregister_trace_uprobe(tu); } + end: mutex_unlock(&uprobe_lock); + return ret; }
/* Probes listing interfaces */ @@ -467,8 +492,13 @@ static const struct seq_operations probes_seq_op = {
static int probes_open(struct inode *inode, struct file *file) { - if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) - cleanup_all_probes(); + int ret; + + if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) { + ret = cleanup_all_probes(); + if (ret < 0) + return ret; + }
return seq_open(file, &probes_seq_op); } @@ -622,11 +652,6 @@ partial: return TRACE_TYPE_PARTIAL_LINE; }
-static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu) -{ - return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE); -} - typedef bool (*filter_func_t)(struct uprobe_consumer *self, enum uprobe_filter_ctx ctx, struct mm_struct *mm); -- 1.7.9.7
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