Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list take 2

[Steven Rostedt <rostedt@goodmis.org>]

On Wed, 2009-09-16 at 11:42 -0400, Masami Hiramatsu wrote:

> Oh, I see, I misunderstood. Thank you for pointing it out. :)
> Here, I updated the patch.

Thanks!

Acked-by: Steven Rostedt <rostedt@goodmis.org> for the whole series.

-- Steve

> 
> ---
> ftrace: Fix trace_add_event_call() to initialize list
> 
> From: Masami Hiramatsu <mhiramat@redhat.com>
> 
> Handle failuer path in trace_add_event_call() for fixing 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:
>  [<c0438424>] warn_slowpath_common+0x65/0x7c
>  [<c05371b3>] ? __list_add+0x27/0x5c
>  [<c043846f>] warn_slowpath_fmt+0x24/0x27
>  [<c05371b3>] __list_add+0x27/0x5c
>  [<c047f050>] list_add+0xa/0xc
>  [<c047f8f5>] trace_add_event_call+0x60/0x97
>  [<c0483133>] command_trace_probe+0x42c/0x51b
>  [<c044a1b3>] ? remove_wait_queue+0x22/0x27
>  [<c042a9c0>] ? __wake_up+0x32/0x3b
>  [<c04832f6>] probes_write+0xd4/0x10a
>  [<c0483222>] ? probes_write+0x0/0x10a
>  [<c04b27a9>] vfs_write+0x80/0xdf
>  [<c04b289c>] sys_write+0x3b/0x5d
>  [<c0670d41>] syscall_call+0x7/0xb
> ---[ end trace 2b962b5dc1fdc07d ]---
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>