On Mon, Jul 01, 2019 at 07:48:26PM +0200, Jann Horn wrote: > On Fri, Jun 28, 2019 at 9:35 PM Joel Fernandes (Google) > <[email protected]> wrote: > > struct pid's count is an atomic_t field used as a refcount. Use > > refcount_t for it which is basically atomic_t but does additional > > checking to prevent use-after-free bugs. > [...] > > struct pid > > { > > - atomic_t count; > > + refcount_t count; > [...] > > diff --git a/kernel/pid.c b/kernel/pid.c > > index 20881598bdfa..89c4849fab5d 100644 > > --- a/kernel/pid.c > > +++ b/kernel/pid.c > > @@ -37,7 +37,7 @@ > > #include <linux/init_task.h> > > #include <linux/syscalls.h> > > #include <linux/proc_ns.h> > > -#include <linux/proc_fs.h> > > +#include <linux/refcount.h> > > #include <linux/sched/task.h> > > #include <linux/idr.h> > > > > @@ -106,8 +106,7 @@ void put_pid(struct pid *pid) > > init_struct_pid is defined as follows: > > struct pid init_struct_pid = { > .count = ATOMIC_INIT(1), > [...] > }; > > This should be changed to REFCOUNT_INIT(1). > > You should have received a compiler warning about this; I get the > following when trying to build with your patch applied:
Thanks. Andrew had fixed this in patch v1 but Linus dropped it for other reasons. Anyway, I should have fixed this in my resubmit. Sorry, I'll fix and resend! - Joel
