From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
"zhangwei(Jovi)" <jovi.zhangwei@huawei.com>,
Jiri Olsa <jolsa@redhat.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Arnaldo Carvalho de Melo <acme@ghostprotocols.net>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [RFC][PATCH 0/4] tracing/kprobes/uprobes: Fix race between opening probe event files and deleting probe
Date: Wed, 03 Jul 2013 23:33:47 -0400 [thread overview]
Message-ID: <20130704033347.807661713@goodmis.org> (raw)
Currently there exists a race with deleting a kprobe or uprobe and
a user opening the probe event file or using perf events.
The problem stems from not being able to take the probe_lock from the
unregister code because we may have the event_mutex at the time, and
the event mutex may be taken with the probe_lock held.
To solve this, the events get a ref count (using the flags field), where
when an event file is opened, the ftrace_event_call ref count increments.
Then this is checked under event_mutex and if set, the unregistering
of the probe will fail.
Here's a test that shows how things break:
# cd /sys/kernel/debug/tracing
# echo 'p:sigprocmask sigprocmask' > kprobe_events || exit -1
# enable_probe() {
sleep 10
echo 1
}
# file=events/kprobes/sigprocmask/enable
# enable_probe > $file &
> kprobe_events
The above will corrupt the kprobe system, as the write to the enable
file will happen after the kprobe was deleted.
Trying to create the probe again fails:
# echo 'p:sigprocmask sigprocmask' > kprobe_events
# cat kprobe_events
p:kprobes/sigprocmask sigprocmask
# ls events/kprobes/
enable filter
After applying these patches, the "> kprobe_events" fails due to the
event being busy.
Masami, please review these patches and give your ack.
Srikar, can you please review the last patch. I didn't test uprobes
with this. I'll do that after the 4th.
Thanks,
-- Steve
Oleg Nesterov (1):
tracing: trace_remove_event_call() should fail if call/file is in use
Steven Rostedt (Red Hat) (3):
tracing: Add ref count to ftrace_event_call
tracing/kprobes: Fail to unregister if probe event files are open
tracing/uprobes: Fail to unregister if probe event files are open
----
include/linux/ftrace_event.h | 8 +++-
kernel/trace/trace_events.c | 109 +++++++++++++++++++++++++++++++++++++++---
kernel/trace/trace_kprobe.c | 21 +++++---
kernel/trace/trace_uprobe.c | 48 ++++++++++++++-----
4 files changed, 160 insertions(+), 26 deletions(-)
next reply other threads:[~2013-07-04 3:40 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-04 3:33 Steven Rostedt [this message]
2013-07-04 3:33 ` [RFC][PATCH 1/4] tracing: Add ref count to ftrace_event_call Steven Rostedt
2013-07-04 4:22 ` Masami Hiramatsu
2013-07-04 11:55 ` [RFC PATCH] tracing: Atomically get refcounts of event_call and trace_array Masami Hiramatsu
2013-07-04 12:12 ` Masami Hiramatsu
2013-07-04 12:23 ` Steven Rostedt
2013-07-05 0:32 ` Oleg Nesterov
2013-07-05 2:32 ` Masami Hiramatsu
2013-07-09 7:55 ` [RFC PATCH V2] tracing: Check f_dentry before accessing event_file/call in inode->i_private Masami Hiramatsu
2013-07-15 18:16 ` Oleg Nesterov
2013-07-17 2:10 ` Masami Hiramatsu
2013-07-17 14:51 ` Oleg Nesterov
2013-07-18 2:20 ` Masami Hiramatsu
2013-07-18 14:51 ` Oleg Nesterov
2013-07-19 5:21 ` Masami Hiramatsu
2013-07-19 13:33 ` Oleg Nesterov
2013-07-22 9:57 ` Masami Hiramatsu
2013-07-22 17:04 ` Oleg Nesterov
2013-07-23 21:04 ` Oleg Nesterov
2013-07-04 3:33 ` [RFC][PATCH 2/4] tracing: trace_remove_event_call() should fail if call/file is in use Steven Rostedt
2013-07-04 12:48 ` Masami Hiramatsu
2013-07-04 3:33 ` [RFC][PATCH 3/4] tracing/kprobes: Fail to unregister if probe event files are open Steven Rostedt
2013-07-04 12:45 ` Masami Hiramatsu
2013-07-04 18:48 ` Oleg Nesterov
2013-07-05 2:53 ` Masami Hiramatsu
2013-07-05 17:26 ` Oleg Nesterov
2013-07-08 2:36 ` Masami Hiramatsu
2013-07-08 14:25 ` Oleg Nesterov
2013-07-09 8:01 ` [RFC PATCH] tracing/kprobe: Wait for disabling all running kprobe handlers Masami Hiramatsu
2013-07-09 8:07 ` Peter Zijlstra
2013-07-09 8:20 ` Masami Hiramatsu
2013-07-09 8:21 ` Peter Zijlstra
2013-07-09 8:50 ` Masami Hiramatsu
2013-07-09 9:35 ` [RFC PATCH V2] " Masami Hiramatsu
2013-07-15 18:20 ` Oleg Nesterov
2013-07-18 12:07 ` Masami Hiramatsu
2013-07-18 14:35 ` Steven Rostedt
2013-07-30 8:15 ` [RFC][PATCH 3/4] tracing/kprobes: Fail to unregister if probe event files are open Masami Hiramatsu
2013-07-31 19:49 ` Steven Rostedt
2013-07-31 20:40 ` Oleg Nesterov
2013-07-31 22:42 ` Steven Rostedt
2013-08-01 2:07 ` Steven Rostedt
2013-08-01 2:50 ` Steven Rostedt
2013-08-01 3:48 ` Masami Hiramatsu
2013-08-01 13:34 ` Oleg Nesterov
2013-08-01 13:49 ` Oleg Nesterov
2013-08-01 14:17 ` Steven Rostedt
2013-08-01 14:33 ` Oleg Nesterov
2013-08-01 14:45 ` Steven Rostedt
2013-08-01 14:46 ` Oleg Nesterov
2013-08-02 4:57 ` Masami Hiramatsu
2013-08-01 13:10 ` Oleg Nesterov
2013-07-04 3:33 ` [RFC][PATCH 4/4] tracing/uprobes: " Steven Rostedt
2013-08-01 3:40 ` Steven Rostedt
2013-08-01 14:08 ` Oleg Nesterov
2013-08-01 14:25 ` Steven Rostedt
2013-07-04 4:00 ` [RFC][PATCH 0/4] tracing/kprobes/uprobes: Fix race between opening probe event files and deleting probe Masami Hiramatsu
2013-07-04 6:14 ` Masami Hiramatsu
2013-07-12 13:09 ` Masami Hiramatsu
2013-07-12 17:53 ` Oleg Nesterov
2013-07-15 18:01 ` Oleg Nesterov
2013-07-16 16:38 ` Oleg Nesterov
2013-07-16 19:10 ` Steven Rostedt
2013-07-16 19:22 ` Oleg Nesterov
2013-07-16 19:38 ` Steven Rostedt
2013-07-17 16:03 ` Steven Rostedt
2013-07-17 17:37 ` Oleg Nesterov
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