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| author |   Li Zefan <lizf@cn.fujitsu.com> | 2009-06-24 09:54:54 +0800 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2009-06-24 11:02:53 +0200 |
| commit | d82d62444f87e5993af2fa82ed636b2206e052ea (patch) | |
| tree | 701f28de7def6c58d80db72a462171cab013b514 /kernel/trace | |
| parent | ftrace: Don't manipulate @pos in t_start() (diff) | |
| download | linux-dev-d82d62444f87e5993af2fa82ed636b2206e052ea.tar.xz linux-dev-d82d62444f87e5993af2fa82ed636b2206e052ea.zip | |
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>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | 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 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) |