Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752537AbdGFALz (ORCPT ); Wed, 5 Jul 2017 20:11:55 -0400 Received: from mail-pf0-f177.google.com ([209.85.192.177]:34310 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752092AbdGFALx (ORCPT ); Wed, 5 Jul 2017 20:11:53 -0400 From: Joel Fernandes To: linux-kernel@vger.kernel.org Cc: mikesart@gmail.com, Joel Fernandes , kernel-team@android.com, Steven Rostedt , Ingo Molnar Subject: [PATCH] tracing: Fix issues recording task information Date: Wed, 5 Jul 2017 17:11:47 -0700 Message-Id: <20170706001147.29213-1-joelaf@google.com> X-Mailer: git-send-email 2.13.2.725.g09c95d1e9-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3003 Lines: 91 Currently we stop recording task information if any of them error out or are not being recorded. Further if switching to/from the idle thread, we bail out early on. Fix these issues. Cc: kernel-team@android.com Cc: Steven Rostedt Cc: Ingo Molnar Reported-by: Michael Sartain Signed-off-by: Joel Fernandes --- Hi Steve, This fix is based on ftrace/core branch at: git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git Could you pick it up for -rc cycle if it looks good to you? Thanks. kernel/trace/trace.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b66a1c8805f3..27b981a46389 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1918,7 +1918,11 @@ static int trace_save_cmdline(struct task_struct *tsk) { unsigned pid, idx; - if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT)) + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + if (unlikely(tsk->pid > PID_MAX_DEFAULT)) return 0; /* @@ -2004,7 +2008,11 @@ int trace_find_tgid(int pid) static int trace_save_tgid(struct task_struct *tsk) { - if (unlikely(!tgid_map || !tsk->pid || tsk->pid > PID_MAX_DEFAULT)) + /* treat recording of idle task as a success */ + if (!tsk->pid) + return 1; + + if (unlikely(!tgid_map || tsk->pid > PID_MAX_DEFAULT)) return 0; tgid_map[tsk->pid] = tsk->tgid; @@ -2031,11 +2039,14 @@ static bool tracing_record_taskinfo_skip(int flags) */ void tracing_record_taskinfo(struct task_struct *task, int flags) { + bool done; + if (tracing_record_taskinfo_skip(flags)) return; - if ((flags & TRACE_RECORD_CMDLINE) && !trace_save_cmdline(task)) - return; - if ((flags & TRACE_RECORD_TGID) && !trace_save_tgid(task)) + + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task); + if (!done) return; __this_cpu_write(trace_taskinfo_save, false); @@ -2052,15 +2063,16 @@ void tracing_record_taskinfo(struct task_struct *task, int flags) void tracing_record_taskinfo_sched_switch(struct task_struct *prev, struct task_struct *next, int flags) { - if (tracing_record_taskinfo_skip(flags)) - return; + bool done; - if ((flags & TRACE_RECORD_CMDLINE) && - (!trace_save_cmdline(prev) || !trace_save_cmdline(next))) + if (tracing_record_taskinfo_skip(flags)) return; - if ((flags & TRACE_RECORD_TGID) && - (!trace_save_tgid(prev) || !trace_save_tgid(next))) + done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev); + done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev); + done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next); + if (!done) return; __this_cpu_write(trace_taskinfo_save, false); -- 2.13.2.725.g09c95d1e9-goog