Pekka, I forgot to add you to the Cc list. Could you test this patch to see if it fixes the bug you reported. It fixed a bug I was able to reproduce, but I was never able to reproduce the exact same bug you have seen. -- Steve On Mon, 10 Nov 2008, Steven Rostedt wrote: > Impact: fix for bug on resize > > This patch addresses the bug found here: > > http://bugzilla.kernel.org/show_bug.cgi?id=11996 > > When ftrace converted to the new unified trace buffer, the resizing of > the buffer was not protected as much as it was originally. If tracing > is performed while the resize occurs, then the buffer can be corrupted. > > This patch disables all ftrace buffer modifications before a resize > takes place. > > Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx> > --- > kernel/trace/trace.c | 17 ++++++++++++++++- > 1 files changed, 16 insertions(+), 1 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 9f3b478..abfa810 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2676,7 +2676,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, > { > unsigned long val; > char buf[64]; > - int ret; > + int ret, cpu; > struct trace_array *tr = filp->private_data; > > if (cnt >= sizeof(buf)) > @@ -2704,6 +2704,14 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, > goto out; > } > > + /* disable all cpu buffers */ > + for_each_tracing_cpu(cpu) { > + if (global_trace.data[cpu]) > + atomic_inc(&global_trace.data[cpu]->disabled); > + if (max_tr.data[cpu]) > + atomic_inc(&max_tr.data[cpu]->disabled); > + } > + > if (val != global_trace.entries) { > ret = ring_buffer_resize(global_trace.buffer, val); > if (ret < 0) { > @@ -2735,6 +2743,13 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, > if (tracing_disabled) > cnt = -ENOMEM; > out: > + for_each_tracing_cpu(cpu) { > + if (global_trace.data[cpu]) > + atomic_dec(&global_trace.data[cpu]->disabled); > + if (max_tr.data[cpu]) > + atomic_dec(&max_tr.data[cpu]->disabled); > + } > + > max_tr.entries = global_trace.entries; > mutex_unlock(&trace_types_lock); > > -- > 1.5.6.5 > > -- > > -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
