On Thu, Mar 28, 2013 at 12:26:03PM +0800, Lingzhu Xiang wrote: > commit 69d34da2984c95b33ea21518227e1f9470f11d95 upstream. > > Backported for 3.4, 3.0-stable. Moved return to after unlock.
Thanks, I'm queuing this for 3.5 kernels as well. Cheers, -- Luis > > From: "Steven Rostedt (Red Hat)" <[email protected]> > > Seems that the tracer flags have never been protected from > synchronous writes. Luckily, admins don't usually modify the > tracing flags via two different tasks. But if scripts were to > be used to modify them, then they could get corrupted. > > Move the trace_types_lock that protects against tracers changing > to also protect the flags being set. > > Cc: [email protected] > Signed-off-by: Steven Rostedt <[email protected]> > Signed-off-by: Lingzhu Xiang <[email protected]> > Reviewed-by: CAI Qian <[email protected]> > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 681a759..a786b6a 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -2768,7 +2768,7 @@ tracing_trace_options_write(struct file *filp, const > char __user *ubuf, > char buf[64]; > char *cmp; > int neg = 0; > - int ret; > + int ret = 0; > int i; > > if (cnt >= sizeof(buf)) > @@ -2785,6 +2785,8 @@ tracing_trace_options_write(struct file *filp, const > char __user *ubuf, > cmp += 2; > } > > + mutex_lock(&trace_types_lock); > + > for (i = 0; trace_options[i]; i++) { > if (strcmp(cmp, trace_options[i]) == 0) { > set_tracer_flags(1 << i, !neg); > @@ -2793,13 +2795,13 @@ tracing_trace_options_write(struct file *filp, const > char __user *ubuf, > } > > /* If no option could be set, test the specific tracer options */ > - if (!trace_options[i]) { > - mutex_lock(&trace_types_lock); > + if (!trace_options[i]) > ret = set_tracer_option(current_trace, cmp, neg); > - mutex_unlock(&trace_types_lock); > - if (ret) > - return ret; > - } > + > + mutex_unlock(&trace_types_lock); > + > + if (ret) > + return ret; > > *ppos += cnt; > > @@ -4486,7 +4488,10 @@ trace_options_core_write(struct file *filp, const char > __user *ubuf, size_t cnt, > > if (val != 0 && val != 1) > return -EINVAL; > + > + mutex_lock(&trace_types_lock); > set_tracer_flags(1 << index, val); > + mutex_unlock(&trace_types_lock); > > *ppos += cnt; > > -- > 1.7.11.7 > > -- > To unsubscribe from this list: send the line "unsubscribe stable" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
