Messages in this thread | | | From | Namhyung Kim <> | Date | Thu, 18 Jun 2020 23:48:45 +0900 | Subject | Re: [PATCH] [perf] Fix null pointer deference in nest_epollfd |
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Hello,
On Thu, Jun 18, 2020 at 9:39 AM Gaurav Singh <gaurav1086@gmail.com> wrote: > > Add a NULL check for worker before dereferencing.
Did you actually see a segfault due to this? It seems it's called with NULL only if multiq is false so there should not be a NULL dereference.
> > Signed-off-by: Gaurav Singh <gaurav1086@gmail.com> > --- > tools/perf/bench/epoll-wait.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/tools/perf/bench/epoll-wait.c b/tools/perf/bench/epoll-wait.c > index 75dca9773186..42983eb7f82e 100644 > --- a/tools/perf/bench/epoll-wait.c > +++ b/tools/perf/bench/epoll-wait.c > @@ -239,6 +239,9 @@ static void *workerfn(void *arg) > > static void nest_epollfd(struct worker *w) > { > + if (!w) > + return; > + > unsigned int i; > struct epoll_event ev; > int efd = multiq ? w->epollfd : epollfd;
Maybe it's more intuitive to check w instead of multiq here.
Thanks Namhyung
> -- > 2.17.1 >
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