Re: system gets stuck in a lock during boot
From: Justin P. Mattock
Date: Sun Aug 23 2009 - 23:07:20 EST
Li Zefan wrote:
CC: Peter, Ingo
Hey alright 2.6.31-rc6 booted.
I must admit, I've been afraid of doing
a git bisect for some time now. but after learning
to do a bisect, I cant see a better solution to finding a
bug(biggest issue I see is having a huge .config).
Anyways the culprit for my issue is this commit:
af6af30c0fcd77e621638e53ef8b176bca8bd3b4
reverting this on rc6 booted the machine up.
Thanks!
Hmm...I don't see how this commit can cause oops:
same here, perf is not enabled at all.
before the git bisect I manually reverted all perf
and came to the conclusion the perf had nothing to do with this.
(must have missed this commit).
@@ -119,11 +119,9 @@ struct ftrace_event_call {
void *filter;
void *mod;
-#ifdef CONFIG_EVENT_PROFILE
- atomic_t profile_count;
- int (*profile_enable)(struct ftrace_event_call *);
- void (*profile_disable)(struct ftrace_event_call *);
-#endif
+ atomic_t profile_count;
+ int (*profile_enable)(struct ftrace_event_call *);
+ void (*profile_disable)(struct ftrace_event_call *);
In your .config, CONFIG_EVENT_PROFILE=y, so this change makes
no difference.
};
#define MAX_FILTER_PRED 32
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profil
index 5b5895a..11ba5bb 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -14,7 +14,7 @@ int ftrace_profile_enable(int event_id)
mutex_lock(&event_mutex);
list_for_each_entry(event,&ftrace_events, list) {
- if (event->id == event_id) {
+ if (event->id == event_id&& event->profile_enable) {
You will run into this hunk only when you run the perf tool,
so should have nothing to do with the boot failure.
I haven't really looked into perf yet, nor have it enabled.
ret = event->profile_enable(event);
break;
}
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 23d2972..e75276a 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentr
entry = trace_create_file("enable", 0644, call->dir, call,
enable);
- if (call->id)
+ if (call->id&& call->profile_enable)
We do an extra check on ->profile_enable, shouldn't cause bug..
maybe this has something to do with SELinux, since I saw with
the oops something with inode_do_init_dentry, and some other stuff
pertaining to SELinux(again though I'm lost as to why I'm hitting this).
entry = trace_create_file("id", 0444, call->dir, call,
id);
Any way, I don't think this commit does the right thing:
- If CONFIG_EVENT_PROFILE=y, we'll create events/<dir>/<event>/id,
except events/ftrace/<event>/id.
- if CONFIG_EVENT_PROFILE=n, there's no 'id' file at all!
I think it's better to skip ftrace/ dir in perf tool code, instead of
skipping creating id files in ftrace code.
can you try this patch:
---
include/linux/ftrace_event.h | 2 ++
kernel/trace/trace_events.c | 2 +-
tools/perf/util/parse-events.c | 8 +++++++-
3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index a81170d..398c925 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -121,9 +121,11 @@ struct ftrace_event_call {
void *filter;
void *mod;
+#ifdef CONFIG_EVENT_PROFILE
atomic_t profile_count;
int (*profile_enable)(struct ftrace_event_call *);
void (*profile_disable)(struct ftrace_event_call *);
+#endif
};
#define MAX_FILTER_PRED 32
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index e75276a..23d2972 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -940,7 +940,7 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
entry = trace_create_file("enable", 0644, call->dir, call,
enable);
- if (call->id&& call->profile_enable)
+ if (call->id)
entry = trace_create_file("id", 0444, call->dir, call,
id);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 0441784..1077ebd 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -113,13 +113,19 @@ static unsigned long hw_cache_stat[C(MAX)] = {
[C(BPU)] = (CACHE_READ),
};
+static int is_tp_subsystem(struct dirent *sys_dir)
+{
+ return !!strcmp(sys_dir->d_name, "ftrace");
+}
+
#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st) \
while (!readdir_r(sys_dir,&sys_dirent,&sys_next)&& sys_next) \
if (snprintf(file, MAXPATHLEN, "%s/%s", debugfs_path, \
sys_dirent.d_name)&& \
(!stat(file,&st))&& (S_ISDIR(st.st_mode))&& \
(strcmp(sys_dirent.d_name, "."))&& \
- (strcmp(sys_dirent.d_name, "..")))
+ (strcmp(sys_dirent.d_name, ".."))&& \
+ (is_tp_subsystem(&sys_dirent)))
static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
{
Alright, in the morning I try this out and let you
know what happens.
Thanks for looking at this.
Justin P. Mattock
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