From 588bebb74fe87270f94c2810652bd683d63c4b54 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 16 Sep 2009 11:42:55 -0400 Subject: [PATCH] ftrace: Fix trace_add_event_call() to initialize list Handle failure path in trace_add_event_call() to fix the below bug which occurred when I tried to add invalid event twice. Could not create debugfs 'kmalloc' directory Failed to register kprobe event: kmalloc Faild to register probe event(-1) ------------[ cut here ]------------ WARNING: at /home/mhiramat/ksrc/random-tracing/lib/list_debug.c:26 __list_add+0x27/0x5c() Hardware name: list_add corruption. next->prev should be prev (c07d78cc), but was 00001000. (next=d854236c). Modules linked in: sunrpc uinput virtio_net virtio_balloon i2c_piix4 pcspkr i2c_core virtio_blk virtio_pci virtio_ring virtio [last unloaded: scsi_wait_scan] Pid: 1394, comm: tee Not tainted 2.6.31-rc9 #51 Call Trace: [] warn_slowpath_common+0x65/0x7c [] ? __list_add+0x27/0x5c [] warn_slowpath_fmt+0x24/0x27 [] __list_add+0x27/0x5c [] list_add+0xa/0xc [] trace_add_event_call+0x60/0x97 [] command_trace_probe+0x42c/0x51b [] ? remove_wait_queue+0x22/0x27 [] ? __wake_up+0x32/0x3b [] probes_write+0xd4/0x10a [] ? probes_write+0x0/0x10a [] vfs_write+0x80/0xdf [] sys_write+0x3b/0x5d [] syscall_call+0x7/0xb ---[ end trace 2b962b5dc1fdc07d ]--- Signed-off-by: Masami Hiramatsu Acked-by: Steven Rostedt Cc: Jim Keniston Cc: Ananth N Mavinakayanahalli Cc: Andi Kleen Cc: Christoph Hellwig Cc: Frank Ch. Eigler Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Jason Baron Cc: K.Prasad Cc: Lai Jiangshan Cc: Li Zefan Cc: Peter Zijlstra Cc: Srikar Dronamraju Cc: Tom Zanussi LKML-Reference: <4AB1077F.6020107@redhat.com> Signed-off-by: Frederic Weisbecker --- kernel/trace/trace_events.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index ba3492076ab2..83cc2c01195d 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1010,9 +1010,12 @@ static int __trace_add_event_call(struct ftrace_event_call *call) return -ENOENT; list_add(&call->list, &ftrace_events); - return event_create_dir(call, d_events, &ftrace_event_id_fops, + ret = event_create_dir(call, d_events, &ftrace_event_id_fops, &ftrace_enable_fops, &ftrace_event_filter_fops, &ftrace_event_format_fops); + if (ret < 0) + list_del(&call->list); + return ret; } /* Add an additional event_call dynamically */ -- 2.20.1