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    Subject[tip:tracing/urgent] tracing: Reset iterator in t_start()
    Commit-ID:  f129e965bef40c6153e4fe505f1e408286213424
    Gitweb: http://git.kernel.org/tip/f129e965bef40c6153e4fe505f1e408286213424
    Author: Li Zefan <lizf@cn.fujitsu.com>
    AuthorDate: Wed, 24 Jun 2009 09:53:44 +0800
    Committer: Ingo Molnar <mingo@elte.hu>
    CommitDate: Wed, 24 Jun 2009 11:02:51 +0200

    tracing: Reset iterator in t_start()

    The iterator is m->private, but it's not reset to trace_types in
    t_start(). If the output is larger than PAGE_SIZE and t_start()
    is called the 2nd time, things will go wrong.

    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: <4A418728.5020506@cn.fujitsu.com>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>


    ---
    kernel/trace/trace.c | 18 ++++--------------
    1 files changed, 4 insertions(+), 14 deletions(-)

    diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
    index 076fa6f..3bb3100 100644
    --- a/kernel/trace/trace.c
    +++ b/kernel/trace/trace.c
    @@ -2053,25 +2053,23 @@ static int tracing_open(struct inode *inode, struct file *file)
    static void *
    t_next(struct seq_file *m, void *v, loff_t *pos)
    {
    - struct tracer *t = m->private;
    + struct tracer *t = v;

    (*pos)++;

    if (t)
    t = t->next;

    - m->private = t;
    -
    return t;
    }

    static void *t_start(struct seq_file *m, loff_t *pos)
    {
    - struct tracer *t = m->private;
    + struct tracer *t;
    loff_t l = 0;

    mutex_lock(&trace_types_lock);
    - for (; t && l < *pos; t = t_next(m, t, &l))
    + for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
    ;

    return t;
    @@ -2107,18 +2105,10 @@ static struct seq_operations show_traces_seq_ops = {

    static int show_traces_open(struct inode *inode, struct file *file)
    {
    - int ret;
    -
    if (tracing_disabled)
    return -ENODEV;

    - ret = seq_open(file, &show_traces_seq_ops);
    - if (!ret) {
    - struct seq_file *m = file->private_data;
    - m->private = trace_types;
    - }
    -
    - return ret;
    + return seq_open(file, &show_traces_seq_ops);
    }

    static ssize_t

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      Last update: 2009-06-24 11:51    [W:0.787 / U:2.096 seconds]
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