trace: remove deprecated entry->cpu

Impact: fix to prevent developers from using entry->cpu

With the new ring buffer infrastructure, the cpu for the entry is
implicit with which CPU buffer it is on.

The original code use to record the current cpu into the generic
entry header, which can be retrieved by entry->cpu. When the
ring buffer was introduced, the users were convert to use the
the cpu number of which cpu ring buffer was in use (this was passed
to the tracers by the iterator: iter->cpu).

Unfortunately, the cpu item in the entry structure was never removed.
This allowed for developers to use it instead of the proper iter->cpu,
unknowingly, using an uninitialized variable. This was not the fault
of the developers, since it would seem like the logical place to
retrieve the cpu identifier.

This patch removes the cpu item from the entry structure and fixes
all the users that should have been using iter->cpu.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fd51cf0b94c7051a707a677ddfca67962679c3f1..bd4d9f8818fa85a3f4303757136c2c94e83d159c 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1531,7 +1531,7 @@ static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 
        if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
                SEQ_PUT_FIELD_RET(s, entry->pid);
-               SEQ_PUT_FIELD_RET(s, entry->cpu);
+               SEQ_PUT_FIELD_RET(s, iter->cpu);
                SEQ_PUT_FIELD_RET(s, iter->ts);
        }
 

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f0c7a0f08cacc8936419b3d5005d97efe1b80959..5efc4c707f7ee943f2eb1af414fd5aa97b2639eb 100644 (file)
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -45,7 +45,6 @@ enum trace_type {
  */
 struct trace_entry {
        unsigned char           type;
-       unsigned char           cpu;
        unsigned char           flags;
        unsigned char           preempt_count;
        int                     pid;

diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index fff3545fc8666c1696beb89e41ba3d6cb214e3be..549238a9b13323fb0a86d5166ea2354ab101bb09 100644 (file)
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -159,7 +159,7 @@ static enum print_line_t bts_trace_print_line(struct trace_iterator *iter)
        trace_assign_type(it, entry);
 
        if (entry->type == TRACE_HW_BRANCHES) {
-               if (trace_seq_printf(seq, "%4d  ", entry->cpu) &&
+               if (trace_seq_printf(seq, "%4d  ", iter->cpu) &&
                    seq_print_ip_sym(seq, it->to, symflags) &&
                    trace_seq_printf(seq, "\t  <-  ") &&
                    seq_print_ip_sym(seq, it->from, symflags) &&
@@ -195,7 +195,6 @@ void trace_hw_branch(u64 from, u64 to)
        entry   = ring_buffer_event_data(event);
        tracing_generic_entry_update(&entry->ent, 0, from);
        entry->ent.type = TRACE_HW_BRANCHES;
-       entry->ent.cpu = cpu;
        entry->from = from;
        entry->to   = to;
        ring_buffer_unlock_commit(tr->buffer, event, irq2);

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b7380eee9fa1c1edd2dc5b166fc3b4ee1f405588..463a310b1d3b5074f72b5016acf21c958c7d2c08 100644 (file)
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -333,7 +333,7 @@ int trace_print_context(struct trace_iterator *iter)
        unsigned long secs = (unsigned long)t;
 
        return trace_seq_printf(s, "%16s-%-5d [%03d] %5lu.%06lu: ",
-                               comm, entry->pid, entry->cpu, secs, usec_rem);
+                               comm, entry->pid, iter->cpu, secs, usec_rem);
 }
 
 int trace_print_lat_context(struct trace_iterator *iter)
@@ -356,7 +356,7 @@ int trace_print_lat_context(struct trace_iterator *iter)
                char *comm = trace_find_cmdline(entry->pid);
                ret = trace_seq_printf(s, "%16s %5d %3d %d %08x %08lx [%08lx]"
                                       " %ld.%03ldms (+%ld.%03ldms): ", comm,
-                                      entry->pid, entry->cpu, entry->flags,
+                                      entry->pid, iter->cpu, entry->flags,
                                       entry->preempt_count, iter->idx,
                                       ns2usecs(iter->ts),
                                       abs_usecs / USEC_PER_MSEC,
@@ -364,7 +364,7 @@ int trace_print_lat_context(struct trace_iterator *iter)
                                       rel_usecs / USEC_PER_MSEC,
                                       rel_usecs % USEC_PER_MSEC);
        } else {
-               ret = lat_print_generic(s, entry, entry->cpu);
+               ret = lat_print_generic(s, entry, iter->cpu);
                if (ret)
                        ret = lat_print_timestamp(s, abs_usecs, rel_usecs);
        }