From 0aff1c0cef13b34c17e81a502336fad738151c37 Mon Sep 17 00:00:00 2001 From: GuoWen Li Date: Wed, 1 Jun 2011 19:18:47 +0800 Subject: ftrace: Fix possible undefined return code kernel/trace/ftrace.c: In function 'ftrace_regex_write.clone.15': kernel/trace/ftrace.c:2743:6: warning: 'ret' may be used uninitialized in this function Signed-off-by: GuoWen Li Link: http://lkml.kernel.org/r/201106011918.47939.guowen.li.linux@gmail.com Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1ee417fcbfa..204b3eb4e69 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2740,7 +2740,7 @@ static int ftrace_process_regex(struct ftrace_hash *hash, { char *func, *command, *next = buff; struct ftrace_func_command *p; - int ret; + int ret = -EINVAL; func = strsep(&next, ":"); -- cgit v1.2.3-70-g09d2 From a4f18ed11a4ddf327dd91cd19e237278600ad327 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 7 Jun 2011 09:26:46 -0400 Subject: ftrace: Revert 8ab2b7efd ftrace: Remove unnecessary disabling of irqs Revert the commit that removed the disabling of interrupts around the initial modifying of mcount callers to nops, and update the comment. The original comment was outdated and stated that the interrupts were being disabled to prevent kstop machine, which was required with the old ftrace daemon, but was no longer the case. What the comment failed to mention was that interrupts needed to be disabled to keep interrupts from preempting the modifying of the code and then executing the code that was partially modified. Revert the commit and update the comment. Reported-by: Richard W.M. Jones Tested-by: Richard W.M. Jones Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 204b3eb4e69..908038f5744 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3330,6 +3330,7 @@ static int ftrace_process_locs(struct module *mod, { unsigned long *p; unsigned long addr; + unsigned long flags; mutex_lock(&ftrace_lock); p = start; @@ -3346,7 +3347,13 @@ static int ftrace_process_locs(struct module *mod, ftrace_record_ip(addr); } + /* + * Disable interrupts to prevent interrupts from executing + * code that is being modified. + */ + local_irq_save(flags); ftrace_update_code(mod); + local_irq_restore(flags); mutex_unlock(&ftrace_lock); return 0; -- cgit v1.2.3-70-g09d2