Messages in this thread | | | Date | Thu, 23 Aug 2018 20:48:49 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] tracing: Fix event filters and triggers to handle negative numbers |
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On Thu, 23 Aug 2018 13:25:34 +0300 Pavel Tikhomirov <ptikhomirov@virtuozzo.com> wrote:
> Then tracing syscall exit event it is extremely useful to filter exit > codes equal to some negative value, to react only to required errors. > But negative numbers does not work: > > [root@snorch sys_exit_read]# echo "ret == -1" > filter > bash: echo: write error: Invalid argument > [root@snorch sys_exit_read]# cat filter > ret == -1 > ^ > parse_error: Invalid value (did you forget quotes)?
Thanks for the patch. I'll apply it and then start testing it!
-- Steve
> > Similar thing happens when setting triggers. > > These is a regression in v4.17 introduced by the commit mentioned below, > testing without these commit shows no problem with negative numbers. > > Fixes: 80765597bc58 ("tracing: Rewrite filter logic to be simpler and faster") > Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> > --- > kernel/trace/trace_events_filter.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index 84a65173b1e9..2ba449292561 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -1299,7 +1299,7 @@ static int parse_pred(const char *str, void *data, > /* go past the last quote */ > i++; > > - } else if (isdigit(str[i])) { > + } else if (isdigit(str[i]) || str[i] == '-') { > > /* Make sure the field is not a string */ > if (is_string_field(field)) { > @@ -1312,6 +1312,9 @@ static int parse_pred(const char *str, void *data, > goto err_free; > } > > + if (str[i] == '-') > + i++; > + > /* We allow 0xDEADBEEF */ > while (isalnum(str[i])) > i++;
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