From: Petr Mladek Date: Mon, 24 Feb 2014 16:12:21 +0000 (+0100) Subject: ftrace: Warn on error when modifying ftrace function X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=cd21067f69240041d36e491ff5597e0217615465;p=linux-beck.git ftrace: Warn on error when modifying ftrace function 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 Signed-off-by: Steven Rostedt --- diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5bd70e8b09b0..0e48ff4cefa5 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -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)