| Message ID | 68ea55d47f10ac8faa0d44e184a5ec00a9dd0409.1659676823.git.yin31149@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | cf8c1e967224c931119d3447f2213d1f645a1a2a |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: enhancements to sk_user_data field | expand |
On Fri, Aug 05, 2022 at 03:48:36PM +0800, Hawkins Jiawei wrote: > Refactor sk_user_data dereference using more generic function > __rcu_dereference_sk_user_data_with_flags(), which improve its > maintainability > > Suggested-by: Jakub Kicinski <kuba@kernel.org> > Signed-off-by: Hawkins Jiawei <yin31149@gmail.com> > --- > kernel/bpf/reuseport_array.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/kernel/bpf/reuseport_array.c b/kernel/bpf/reuseport_array.c > index e2618fb5870e..85fa9dbfa8bf 100644 > --- a/kernel/bpf/reuseport_array.c > +++ b/kernel/bpf/reuseport_array.c > @@ -21,14 +21,11 @@ static struct reuseport_array *reuseport_array(struct bpf_map *map) > /* The caller must hold the reuseport_lock */ > void bpf_sk_reuseport_detach(struct sock *sk) > { > - uintptr_t sk_user_data; > + struct sock __rcu **socks; > > write_lock_bh(&sk->sk_callback_lock); > - sk_user_data = (uintptr_t)sk->sk_user_data; > - if (sk_user_data & SK_USER_DATA_BPF) { > - struct sock __rcu **socks; > - > - socks = (void *)(sk_user_data & SK_USER_DATA_PTRMASK); > + socks = __rcu_dereference_sk_user_data_with_flags(sk, SK_USER_DATA_BPF); syzbot reports 'suspicious rcu_dereference_check() usage': https://lore.kernel.org/netdev/0000000000007902fc05e6458697@google.com/ rcu_read_lock() does not need to be held here. One option is to use rcu_access_pointer. Another option is to use rcu_dereference_check() and pass the lockdep_is_held(&sk->sk_callback_lock) from here. > + if (socks) { > WRITE_ONCE(sk->sk_user_data, NULL); > /* > * Do not move this NULL assignment outside of > -- > 2.25.1 >
diff --git a/kernel/bpf/reuseport_array.c b/kernel/bpf/reuseport_array.c index e2618fb5870e..85fa9dbfa8bf 100644 --- a/kernel/bpf/reuseport_array.c +++ b/kernel/bpf/reuseport_array.c @@ -21,14 +21,11 @@ static struct reuseport_array *reuseport_array(struct bpf_map *map) /* The caller must hold the reuseport_lock */ void bpf_sk_reuseport_detach(struct sock *sk) { - uintptr_t sk_user_data; + struct sock __rcu **socks; write_lock_bh(&sk->sk_callback_lock); - sk_user_data = (uintptr_t)sk->sk_user_data; - if (sk_user_data & SK_USER_DATA_BPF) { - struct sock __rcu **socks; - - socks = (void *)(sk_user_data & SK_USER_DATA_PTRMASK); + socks = __rcu_dereference_sk_user_data_with_flags(sk, SK_USER_DATA_BPF); + if (socks) { WRITE_ONCE(sk->sk_user_data, NULL); /* * Do not move this NULL assignment outside of
Refactor sk_user_data dereference using more generic function __rcu_dereference_sk_user_data_with_flags(), which improve its maintainability Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Hawkins Jiawei <yin31149@gmail.com> --- kernel/bpf/reuseport_array.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)