On Tue, May 20, 2025 at 1:08 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Mon, May 19, 2025 at 10:51 PM Xuewen Yan <xuewen.yan@xxxxxxxxxx> wrote:
> >
> > From: Di Shen <di.shen@xxxxxxxxxx>
> >
> > This reverts commit 4a8f635a60540888dab3804992e86410360339c8.
> >
> > Althought get_pid_task() internally already calls rcu_read_lock() and
> > rcu_read_unlock(), the find_vpid() was not.
> >
> > The documentation for find_vpid() clearly states:
> >
> > "Must be called with the tasklist_lock or rcu_read_lock() held."
> >
> > Add proper rcu_read_lock/unlock() to protect the find_vpid().
> >
> > Reported-by: Xuewen Yan <xuewen.yan@xxxxxxxxxx>
> > Signed-off-by: Di Shen <di.shen@xxxxxxxxxx>
> > ---
> > kernel/trace/bpf_trace.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > index 187dc37d61d4..0c4b6af10601 100644
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
> > @@ -3417,7 +3417,9 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr
> > }
> >
> > if (pid) {
> > + rcu_read_lock();
> > task = get_pid_task(find_vpid(pid), PIDTYPE_TGID);
> > + rcu_read_unlock();
> > if (!task) {
> > err = -ESRCH;
> > goto error_path_put;
>
> hmm. indeed.
>
yep, my bad, missed find_vpid() restrictions. revert LGTM
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> Jiri ?
