Messages in this thread | | | Date | Wed, 17 Jun 2009 07:06:07 +0200 | From | Frederic Weisbecker <> | Subject | Re: [Patch 1/2] ksym_tracer:Fix line-wrapping after removal of ksym tracer entry |
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On Wed, Jun 17, 2009 at 04:35:04AM +0530, K.Prasad wrote: > Removal of a ksym entry results in missing information and an early return with > TRACE_TYPE_PARTIAL_LINE code (minus the line return). This patch modifies the > output function to unconditionally add a line return irrespective of the > return code. > > Signed-off-by: K.Prasad <prasad@linux.vnet.ibm.com> > --- > kernel/trace/trace_ksym.c | 27 +++++++++++++++------------ > 1 file changed, 15 insertions(+), 12 deletions(-) > > Index: linux-2.6-tip.hbkpt/kernel/trace/trace_ksym.c > =================================================================== > --- linux-2.6-tip.hbkpt.orig/kernel/trace/trace_ksym.c > +++ linux-2.6-tip.hbkpt/kernel/trace/trace_ksym.c > @@ -391,29 +391,32 @@ static enum print_line_t ksym_trace_outp > > ret = trace_seq_printf(s, "%-15s %-5d %-3d %-20s ", field->p_name, > entry->pid, iter->cpu, field->ksym_name); > - if (!ret) > - return TRACE_TYPE_PARTIAL_LINE; > + if (!ret) { > + ret = TRACE_TYPE_PARTIAL_LINE; > + goto err_ret; > + } > > + ret = TRACE_TYPE_PARTIAL_LINE; > switch (field->ksym_hbp->info.type) { > case HW_BREAKPOINT_WRITE: > - ret = trace_seq_printf(s, " W "); > + if (!trace_seq_printf(s, " W ")) > + goto err_ret; > break; > case HW_BREAKPOINT_RW: > - ret = trace_seq_printf(s, " RW "); > + if (!trace_seq_printf(s, " RW ")) > + goto err_ret; > break; > default: > - return TRACE_TYPE_PARTIAL_LINE; > + goto err_ret; > } > > - if (!ret) > - return TRACE_TYPE_PARTIAL_LINE; > - > sprint_symbol(str, field->ip); > ret = trace_seq_printf(s, "%-20s\n", str); > - if (!ret) > - return TRACE_TYPE_PARTIAL_LINE; > - > - return TRACE_TYPE_HANDLED; > + if (ret) > + return TRACE_TYPE_HANDLED; > +err_ret: > + trace_seq_printf(s, "\n"); > + return ret;
As told in my email just before, TRACE_TYPE_PARTIAL_LINE won't print a truncated line or a partial line. Instead, it will be ignored and entirely retried later. Then your newline will be ignored.
..unless we have a bug in trace.c
I'm not sure what it the origin of the concatenated printed entries Ingo has reported.
Did you reproduce it and then this patch fixed it?
> } > > struct tracer ksym_tracer __read_mostly = >
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