Messages in this thread Patch in this message | | | Date | Wed, 24 Jun 2009 09:46:55 GMT | From | tip-bot for Li Zefan <> | Subject | [tip:tracing/urgent] ftrace: Fix t_hash_start() |
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Commit-ID: d82d62444f87e5993af2fa82ed636b2206e052ea Gitweb: http://git.kernel.org/tip/d82d62444f87e5993af2fa82ed636b2206e052ea Author: Li Zefan <lizf@cn.fujitsu.com> AuthorDate: Wed, 24 Jun 2009 09:54:54 +0800 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Wed, 24 Jun 2009 11:02:53 +0200
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 <liming.wang@windriver.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A41876E.2060407@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- kernel/trace/ftrace.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index dc81020..71a52c1 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)
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