diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2017-05-17 10:19:49 +0200 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-09-15 18:29:43 +0100 |
| commit | fb73e0b6deb05390038a4e313d06fe81f96e0eab (patch) | |
| tree | c063c39e92a372ffa44df3588b6920086e09bbc2 /kernel | |
| parent | 18e102517a263fcbb410cee0d4837febc6c09222 (diff) | |
tracing/kprobes: Enforce kprobes teardown after testing
commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream.
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>
Fixes: 6274de498 ("kprobes: Support delayed unoptimizing")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kprobes.c | 2 | ||||
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 5 |
2 files changed, 6 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 734e9a7d280b..f6397bb4d5f6 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -563,7 +563,7 @@ 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 282f6e4e5539..b53aa5b9c038 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1484,6 +1484,11 @@ 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 |