From 85951842a1020669f0a9eb0f0d1853b41341f097 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 24 Jun 2009 09:54:00 +0800 Subject: ftrace: Don't increment @pos in g_start() It's wrong to increment @pos in g_start(). It causes some entries lost when reading set_graph_function, if the output of the file is larger than PAGE_SIZE. Reviewed-by: Liming Wang Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4A418738.7090401@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3718d55fb4c3..cde74b9973b7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2500,32 +2500,31 @@ int ftrace_graph_count; unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly; static void * -g_next(struct seq_file *m, void *v, loff_t *pos) +__g_next(struct seq_file *m, loff_t *pos) { unsigned long *array = m->private; - int index = *pos; - - (*pos)++; - if (index >= ftrace_graph_count) + if (*pos >= ftrace_graph_count) return NULL; + return &array[*pos]; +} - return &array[index]; +static void * +g_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return __g_next(m, pos); } static void *g_start(struct seq_file *m, loff_t *pos) { - void *p = NULL; - mutex_lock(&graph_lock); /* Nothing, tell g_show to print all functions are enabled */ if (!ftrace_graph_count && !*pos) return (void *)1; - p = g_next(m, p, pos); - - return p; + return __g_next(m, pos); } static void g_stop(struct seq_file *m, void *p) -- cgit v1.2.2 From 694ce0a544fba37a60025a6803ee6265be8a2a22 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 24 Jun 2009 09:54:19 +0800 Subject: ftrace: Don't manipulate @pos in t_start() It's rather confusing that in t_start(), in some cases @pos is incremented, and in some cases it's decremented and then incremented. This patch rewrites t_start() in a much more general way. Thus we fix a bug that if ftrace_filtered == 1, functions have tracer hooks won't be printed, because the branch is always unreachable: static void *t_start(...) { ... if (!p) return t_hash_start(m, pos); return p; } Before: # echo 'sys_open' > /mnt/tracing/set_ftrace_filter # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter sys_open After: # echo 'sys_open' > /mnt/tracing/set_ftrace_filter # echo 'sys_write:traceon:4' >> /mnt/tracing/set_ftrace_filter sys_open sys_write:traceon:count=4 Reviewed-by: Liming Wang Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4A41874B.4090507@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index cde74b9973b7..dc810208edde 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1467,8 +1467,6 @@ t_next(struct seq_file *m, void *v, loff_t *pos) iter->pg = iter->pg->next; iter->idx = 0; goto retry; - } else { - iter->idx = -1; } } else { rec = &iter->pg->records[iter->idx++]; @@ -1497,6 +1495,7 @@ static void *t_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; + loff_t l; mutex_lock(&ftrace_lock); /* @@ -1508,23 +1507,21 @@ static void *t_start(struct seq_file *m, loff_t *pos) if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; - (*pos)++; return iter; } if (iter->flags & FTRACE_ITER_HASH) return t_hash_start(m, pos); - if (*pos > 0) { - if (iter->idx < 0) - return p; - (*pos)--; - iter->idx--; + iter->pg = ftrace_pages_start; + iter->idx = 0; + for (l = 0; l <= *pos; ) { + p = t_next(m, p, &l); + if (!p) + break; } - p = t_next(m, p, pos); - - if (!p) + if (!p && iter->flags & FTRACE_ITER_FILTER) return t_hash_start(m, pos); return p; -- cgit v1.2.2 From d82d62444f87e5993af2fa82ed636b2206e052ea Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Wed, 24 Jun 2009 09:54:54 +0800 Subject: ftrace: Fix t_hash_start() When the output of set_ftrace_filter is larger than PAGE_SIZE, t_hash_start() will be called the 2nd time, and then we start from the head of a hlist, which is wrong and causes some entries to be outputed twice. The worse is, if the hlist is large enough, reading set_ftrace_filter won't stop but in a dead loop. Reviewed-by: Liming Wang Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4A41876E.2060407@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dc810208edde..71a52c172140 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1417,10 +1417,20 @@ static void *t_hash_start(struct seq_file *m, loff_t *pos) { struct ftrace_iterator *iter = m->private; void *p = NULL; + loff_t l; + + if (!(iter->flags & FTRACE_ITER_HASH)) + *pos = 0; iter->flags |= FTRACE_ITER_HASH; - return t_hash_next(m, p, pos); + iter->hidx = 0; + for (l = 0; l <= *pos; ) { + p = t_hash_next(m, p, &l); + if (!p) + break; + } + return p; } static int t_hash_show(struct seq_file *m, void *v) -- cgit v1.2.2 From 0296e4254f3318e0dcad9706fa1daf8e5addc1e9 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 26 Jun 2009 11:15:37 +0800 Subject: ftrace: Fix the output of profile The first entry of the ftrace profile was always skipped when reading trace_stat/functionX. Signed-off-by: Li Zefan Cc: Steven Rostedt Cc: Frederic Weisbecker LKML-Reference: <4A443D59.4080307@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/ftrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 71a52c172140..f3716bf04df6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -291,7 +291,9 @@ function_stat_next(void *v, int idx) pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK); again: - rec++; + if (idx != 0) + rec++; + if ((void *)rec >= (void *)&pg->records[pg->index]) { pg = pg->next; if (!pg) -- cgit v1.2.2