Messages in this thread Patch in this message | | | From | Vasily Averin <> | Subject | [PATCH 3/7] t_next should increase position index | Date | Fri, 24 Jan 2020 10:02:51 +0300 |
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if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output.
https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin <vvs@virtuozzo.com> --- kernel/trace/ftrace.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 9bf1f2c..ca25210 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3442,8 +3442,10 @@ static void *t_mod_start(struct seq_file *m, loff_t *pos) loff_t l = *pos; /* t_probe_start() must use original pos */ void *ret; - if (unlikely(ftrace_disabled)) + if (unlikely(ftrace_disabled)) { + (*pos)++; return NULL; + } if (iter->flags & FTRACE_ITER_PROBE) return t_probe_next(m, pos); -- 1.8.3.1
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