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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-11 02:58:10 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-11 02:58:10 (GMT) |
commit | 991ec02cdca33b03a132a0cacfe6f0aa0be9aa8d (patch) | |
tree | 50b5f4e2b9f138da57f76eca44fdcc80a2fcd428 /kernel/trace/ftrace.c | |
parent | 862366118026a358882eefc70238dbcc3db37aac (diff) | |
parent | 84047e360af0394ac5861d433f26bbcf30f77dd1 (diff) | |
download | linux-fsl-qoriq-991ec02cdca33b03a132a0cacfe6f0aa0be9aa8d.tar.xz |
Merge branch 'tracing-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
function-graph: always initialize task ret_stack
function-graph: move initialization of new tasks up in fork
function-graph: add memory barriers for accessing task's ret_stack
function-graph: enable the stack after initialization of other variables
function-graph: only allocate init tasks if it was not already done
Manually fix trivial conflict in kernel/trace/ftrace.c
Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r-- | kernel/trace/ftrace.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d6973df..bb60732 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3218,12 +3218,12 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) } if (t->ret_stack == NULL) { - t->curr_ret_stack = -1; - /* Make sure IRQs see the -1 first: */ - barrier(); - t->ret_stack = ret_stack_list[start++]; atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); + t->curr_ret_stack = -1; + /* Make sure the tasks see the -1 first: */ + smp_wmb(); + t->ret_stack = ret_stack_list[start++]; } } while_each_thread(g, t); @@ -3281,8 +3281,10 @@ static int start_graph_tracing(void) return -ENOMEM; /* The cpu_boot init_task->ret_stack will never be freed */ - for_each_online_cpu(cpu) - ftrace_graph_init_task(idle_task(cpu)); + for_each_online_cpu(cpu) { + if (!idle_task(cpu)->ret_stack) + ftrace_graph_init_task(idle_task(cpu)); + } do { ret = alloc_retstack_tasklist(ret_stack_list); @@ -3374,18 +3376,25 @@ void unregister_ftrace_graph(void) /* Allocate a return stack for newly created task */ void ftrace_graph_init_task(struct task_struct *t) { + /* Make sure we do not use the parent ret_stack */ + t->ret_stack = NULL; + if (ftrace_graph_active) { - t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH + struct ftrace_ret_stack *ret_stack; + + ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH * sizeof(struct ftrace_ret_stack), GFP_KERNEL); - if (!t->ret_stack) + if (!ret_stack) return; t->curr_ret_stack = -1; atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->ftrace_timestamp = 0; - } else - t->ret_stack = NULL; + /* make curr_ret_stack visable before we add the ret_stack */ + smp_wmb(); + t->ret_stack = ret_stack; + } } void ftrace_graph_exit_task(struct task_struct *t) |