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authorThomas Gleixner <tglx@linutronix.de>2017-05-17 11:19:49 +0300
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-05-18 04:50:27 +0300
commit30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd (patch)
tree98e2513897c6bf963bb046542062007a7476c6ea /kernel
parentb9ef0326c05a008c3c576bd4d676208b50c344d5 (diff)
downloadlinux-30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd.tar.xz
tracing/kprobes: Enforce kprobes teardown after testing
Enabling the tracer selftest triggers occasionally the warning in text_poke(), which warns when the to be modified page is not marked reserved. The reason is that the tracer selftest installs kprobes on functions marked __init for testing. These probes are removed after the tests, but that removal schedules the delayed kprobes_optimizer work, which will do the actual text poke. If the work is executed after the init text is freed, then the warning triggers. The bug can be reproduced reliably when the work delay is increased. Flush the optimizer work and wait for the optimizing/unoptimizing lists to become empty before returning from the kprobes tracer selftest. That ensures that all operations which were queued due to the probes removal have completed. Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c2
-rw-r--r--kernel/trace/trace_kprobe.c5
2 files changed, 6 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 7367e0ec6f81..199243bba554 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -595,7 +595,7 @@ static void kprobe_optimizer(struct work_struct *work)
}
/* Wait for completing optimization and unoptimization */
-static void wait_for_kprobe_optimizer(void)
+void wait_for_kprobe_optimizer(void)
{
mutex_lock(&kprobe_mutex);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 8485f6738a87..c129fca6ec99 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1535,6 +1535,11 @@ static __init int kprobe_trace_self_tests_init(void)
end:
release_all_trace_kprobes();
+ /*
+ * Wait for the optimizer work to finish. Otherwise it might fiddle
+ * with probes in already freed __init text.
+ */
+ wait_for_kprobe_optimizer();
if (warn)
pr_cont("NG: Some tests are failed. Please check them.\n");
else