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SubjectRe: [PATCH 1/8] trace: remove deprecated entry->cpu
On Sun, Feb 08, 2009 at 12:49:56AM -0500, Steven Rostedt wrote:
> From: Steven Rostedt <srostedt@redhat.com>
>
> 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>



Heh, we have sent the same patch at very few different hours...
Funny :-)


> ---
> kernel/trace/trace.c | 2 +-
> kernel/trace/trace.h | 1 -
> kernel/trace/trace_hw_branches.c | 3 +--
> kernel/trace/trace_output.c | 6 +++---
> 4 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index fd51cf0..bd4d9f8 100644
> --- 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 f0c7a0f..5efc4c7 100644
> --- 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 fff3545..549238a 100644
> --- 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 b7380ee..463a310 100644
> --- 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);
> }
> --
> 1.5.6.5
>
> --



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