Merge tag 'trace-fixes-v3.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Oleg Nesterov found and fixed a bug in the perf/ftrace/uprobes code
where running:
# perf probe -x /lib/libc.so.6 syscall
# echo 1 >> /sys/kernel/debug/tracing/events/probe_libc/enable
# perf record -e probe_libc:syscall whatever
kills the uprobe. Along the way he found some other minor bugs and
clean ups that he fixed up making it a total of 4 patches.
Doing unrelated work, I found that the reading of the ftrace trace
file disables all function tracer callbacks. This was fine when
ftrace was the only user, but now that it's used by perf and kprobes,
this is a bug where reading trace can disable kprobes and perf. A
very unexpected side effect and should be fixed"
* tag 'trace-fixes-v3.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Remove ftrace_stop/start() from reading the trace file
tracing/uprobes: Fix the usage of uprobe_buffer_enable() in probe_event_enable()
tracing/uprobes: Kill the bogus UPROBE_HANDLER_REMOVE code in uprobe_dispatcher()
uprobes: Change unregister/apply to WARN() if uprobe/consumer is gone
tracing/uprobes: Revert "Support mix of ftrace and perf"
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index c445e39..6f3254e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -846,7 +846,7 @@
{
int err;
- if (!consumer_del(uprobe, uc)) /* WARN? */
+ if (WARN_ON(!consumer_del(uprobe, uc)))
return;
err = register_for_each_vma(uprobe, NULL);
@@ -927,7 +927,7 @@
int ret = -ENOENT;
uprobe = find_uprobe(inode, offset);
- if (!uprobe)
+ if (WARN_ON(!uprobe))
return ret;
down_write(&uprobe->register_rwsem);
@@ -952,7 +952,7 @@
struct uprobe *uprobe;
uprobe = find_uprobe(inode, offset);
- if (!uprobe)
+ if (WARN_ON(!uprobe))
return;
down_write(&uprobe->register_rwsem);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 384ede3..f243444 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1396,7 +1396,6 @@
arch_spin_unlock(&global_trace.max_lock);
- ftrace_start();
out:
raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
}
@@ -1443,7 +1442,6 @@
struct ring_buffer *buffer;
unsigned long flags;
- ftrace_stop();
raw_spin_lock_irqsave(&global_trace.start_lock, flags);
if (global_trace.stop_count++)
goto out;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 04fdb5d..3c9b97e 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -893,6 +893,9 @@
int ret;
if (file) {
+ if (tu->tp.flags & TP_FLAG_PROFILE)
+ return -EINTR;
+
link = kmalloc(sizeof(*link), GFP_KERNEL);
if (!link)
return -ENOMEM;
@@ -901,29 +904,40 @@
list_add_tail_rcu(&link->list, &tu->tp.files);
tu->tp.flags |= TP_FLAG_TRACE;
- } else
- tu->tp.flags |= TP_FLAG_PROFILE;
+ } else {
+ if (tu->tp.flags & TP_FLAG_TRACE)
+ return -EINTR;
- ret = uprobe_buffer_enable();
- if (ret < 0)
- return ret;
+ tu->tp.flags |= TP_FLAG_PROFILE;
+ }
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;
}
@@ -1201,12 +1215,6 @@
current->utask->vaddr = (unsigned long) &udd;
-#ifdef CONFIG_PERF_EVENTS
- if ((tu->tp.flags & TP_FLAG_TRACE) == 0 &&
- !uprobe_perf_filter(&tu->consumer, 0, current->mm))
- return UPROBE_HANDLER_REMOVE;
-#endif
-
if (WARN_ON_ONCE(!uprobe_cpu_buffer))
return 0;