Messages in this thread | | | Subject | Re: [PATCH tracing/kprobes 2/6] ftrace: Fix trace_add_event_call() to initialize list | From | Steven Rostedt <> | Date | Tue, 15 Sep 2009 19:51:21 -0400 |
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On Mon, 2009-09-14 at 16:49 -0400, Masami Hiramatsu wrote: > Initialize event_call.list and 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> > Cc: Jim Keniston <jkenisto@us.ibm.com> > Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> > Cc: Andi Kleen <ak@linux.intel.com> > Cc: Christoph Hellwig <hch@infradead.org> > Cc: Frank Ch. Eigler <fche@redhat.com> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: H. Peter Anvin <hpa@zytor.com> > Cc: Ingo Molnar <mingo@elte.hu> > Cc: Jason Baron <jbaron@redhat.com> > Cc: K.Prasad <prasad@linux.vnet.ibm.com> > Cc: Lai Jiangshan <laijs@cn.fujitsu.com> > Cc: Li Zefan <lizf@cn.fujitsu.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Tom Zanussi <tzanussi@gmail.com> > --- > > kernel/trace/trace_events.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index ba34920..38e82a5 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -1009,10 +1009,14 @@ static int __trace_add_event_call(struct ftrace_event_call *call) > if (!d_events) > return -ENOENT; > > + INIT_LIST_HEAD(&call->list);
The INIT_LIST_HEAD is not needed here. The list_add will assign it.
> 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);
But this I can see is needed ;-)
-- Steve
> + return ret; > } > > /* Add an additional event_call dynamically */ > >
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