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This fixes a long standing bug in the ftrace profiler.

Browse Source 
The problem is that the profiler only initializes the online
 CPUs, and not possible CPUs. This causes issues if the user takes
 CPUs online or offline while the profiler is running.
 
 If we online a CPU after starting the profiler, we lose all the
 trace information on the CPU going online.
 
 If we offline a CPU after running a test and start a new test, it
 will not clear the old data from that CPU.
 
 This bug causes incorrect data to be reported to the user if they
 online or offline CPUs during the profiling.
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Merge tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull ftrace fix from Steven Rostedt:
 "This fixes a long standing bug in the ftrace profiler.  The problem is
  that the profiler only initializes the online CPUs, and not possible
  CPUs.  This causes issues if the user takes CPUs online or offline
  while the profiler is running.

  If we online a CPU after starting the profiler, we lose all the trace
  information on the CPU going online.

  If we offline a CPU after running a test and start a new test, it will
  not clear the old data from that CPU.

  This bug causes incorrect data to be reported to the user if they
  online or offline CPUs during the profiling"

* tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Initialize the ftrace profiler for each possible cpu
This commit is contained in:
Linus Torvalds 2013-12-20 09:32:30 -08:00
commit 5263f0a880
1 changed files with 1 additions and 1 deletions
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2
kernel/trace/ftrace.c
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@ -775,7 +775,7 @@ static int ftrace_profile_init(void)
int cpu;
int ret = 0;
for_each_online_cpu(cpu) {
for_each_possible_cpu(cpu) {
ret = ftrace_profile_init_cpu(cpu);
if (ret)
break;