Messages in this thread | | | Subject | Re: [PATCH 3/7] t_next should increase position index | From | Vasily Averin <> | Date | Thu, 30 Jan 2020 10:17:53 +0300 |
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On 1/29/20 8:12 PM, Steven Rostedt wrote: > On Fri, 24 Jan 2020 10:02:51 +0300 > Vasily Averin <vvs@virtuozzo.com> wrote: > >> 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; >> + } > > This isn't needed. If ftrace_disabled is set, we shouldn't be printing > anything. This case isn't the same as the report in the bugzilla.
I'm agree, thank you, let's drop this patch.
Vasily Averin
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