From fb6bab6a5ad46d00b5ffa22268f21df1cd7c59df Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Fri, 27 Jun 2014 19:01:46 +0200 Subject: [PATCH] tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable() The usage of uprobe_buffer_enable() added by dcad1a20 is very wrong, 1. uprobe_buffer_enable() and uprobe_buffer_disable() are not balanced, _enable() should be called only if !enabled. 2. If uprobe_buffer_enable() fails probe_event_enable() should clear tp.flags and free event_file_link. 3. If uprobe_register() fails it should do uprobe_buffer_disable(). Link: http://lkml.kernel.org/p/20140627170146.GA18332@redhat.com Acked-by: Namhyung Kim Acked-by: Srikar Dronamraju Reviewed-by: Masami Hiramatsu Fixes: dcad1a204f72 "tracing/uprobes: Fetch args before reserving a ring buffer" Signed-off-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/trace_uprobe.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index c4cf0abd60ba..3c9b97e6b1f4 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -911,26 +911,33 @@ probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file, tu->tp.flags |= TP_FLAG_PROFILE; } - ret = uprobe_buffer_enable(); - if (ret < 0) - return ret; - WARN_ON(!uprobe_filter_is_empty(&tu->filter)); if (enabled) return 0; + ret = uprobe_buffer_enable(); + if (ret) + goto err_flags; + tu->consumer.filter = filter; ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); - if (ret) { - if (file) { - list_del(&link->list); - kfree(link); - tu->tp.flags &= ~TP_FLAG_TRACE; - } else - tu->tp.flags &= ~TP_FLAG_PROFILE; - } + if (ret) + goto err_buffer; + return 0; + + err_buffer: + uprobe_buffer_disable(); + + err_flags: + if (file) { + list_del(&link->list); + kfree(link); + tu->tp.flags &= ~TP_FLAG_TRACE; + } else { + tu->tp.flags &= ~TP_FLAG_PROFILE; + } return ret; } -- 2.11.0