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ftrace: Warn on error when modifying ftrace function

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We should print some warning and kill ftrace functionality when the ftrace
function is not set correctly. Otherwise, ftrace might do crazy things without
an explanation. The error value has been ignored so far.

Note that an error that happens during updating all the traced calls is handled
in ftrace_replace_code(). We print more details about the particular
failing address via ftrace_bug() there.

Link: http://lkml.kernel.org/r/1393258342-29978-3-git-send-email-pmladek@suse.cz

Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Petr Mladek 2014-02-24 17:12:21 +01:00 committed by Steven Rostedt
parent a762782d78
commit cd21067f69
1 changed files with 12 additions and 5 deletions
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17
kernel/trace/ftrace.c
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@ -1994,6 +1994,7 @@ int __weak ftrace_arch_code_modify_post_process(void)
void ftrace_modify_all_code(int command)
{
int update = command & FTRACE_UPDATE_TRACE_FUNC;
int err = 0;
/*
* If the ftrace_caller calls a ftrace_ops func directly,
@ -2005,8 +2006,11 @@ void ftrace_modify_all_code(int command)
* to make sure the ops are having the right functions
* traced.
*/
if (update)
ftrace_update_ftrace_func(ftrace_ops_list_func);
if (update) {
err = ftrace_update_ftrace_func(ftrace_ops_list_func);
if (FTRACE_WARN_ON(err))
return;
}
if (command & FTRACE_UPDATE_CALLS)
ftrace_replace_code(1);
@ -2019,13 +2023,16 @@ void ftrace_modify_all_code(int command)
/* If irqs are disabled, we are in stop machine */
if (!irqs_disabled())
smp_call_function(ftrace_sync_ipi, NULL, 1);
ftrace_update_ftrace_func(ftrace_trace_function);
err = ftrace_update_ftrace_func(ftrace_trace_function);
if (FTRACE_WARN_ON(err))
return;
}
if (command & FTRACE_START_FUNC_RET)
ftrace_enable_ftrace_graph_caller();
err = ftrace_enable_ftrace_graph_caller();
else if (command & FTRACE_STOP_FUNC_RET)
ftrace_disable_ftrace_graph_caller();
err = ftrace_disable_ftrace_graph_caller();
FTRACE_WARN_ON(err);
}
static int __ftrace_modify_code(void *data)