From df1a2cb7c74b3d3abc8d8c2d690f82c8ebc3490a Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 12 Feb 2019 15:42:38 -0800 Subject: bpf/test_run: fix unkillable BPF_PROG_TEST_RUN Syzbot found out that running BPF_PROG_TEST_RUN with repeat=0xffffffff makes process unkillable. The problem is that when CONFIG_PREEMPT is enabled, we never see need_resched() return true. This is due to the fact that preempt_enable() (which we do in bpf_test_run_one on each iteration) now handles resched if it's needed. Let's disable preemption for the whole run, not per test. In this case we can properly see whether resched is needed. Let's also properly return -EINTR to the userspace in case of a signal interrupt. See recent discussion: http://lore.kernel.org/netdev/CAH3MdRWHr4N8jei8jxDppXjmw-Nw=puNDLbu1dQOFQHxfU2onA@mail.gmail.com I'll follow up with the same fix bpf_prog_test_run_flow_dissector in bpf-next. Reported-by: syzbot Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann --- net/bpf/test_run.c | 45 ++++++++++++++++++++++++--------------------- 1 file changed, 24 insertions(+), 21 deletions(-) (limited to 'net') diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index fa2644d276ef..e31e1b20f7f4 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -13,27 +13,13 @@ #include #include -static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx, - struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) -{ - u32 ret; - - preempt_disable(); - rcu_read_lock(); - bpf_cgroup_storage_set(storage); - ret = BPF_PROG_RUN(prog, ctx); - rcu_read_unlock(); - preempt_enable(); - - return ret; -} - -static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *ret, - u32 *time) +static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, + u32 *retval, u32 *time) { struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = { 0 }; enum bpf_cgroup_storage_type stype; u64 time_start, time_spent = 0; + int ret = 0; u32 i; for_each_cgroup_storage_type(stype) { @@ -48,25 +34,42 @@ static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *ret, if (!repeat) repeat = 1; + + rcu_read_lock(); + preempt_disable(); time_start = ktime_get_ns(); for (i = 0; i < repeat; i++) { - *ret = bpf_test_run_one(prog, ctx, storage); + bpf_cgroup_storage_set(storage); + *retval = BPF_PROG_RUN(prog, ctx); + + if (signal_pending(current)) { + ret = -EINTR; + break; + } + if (need_resched()) { - if (signal_pending(current)) - break; time_spent += ktime_get_ns() - time_start; + preempt_enable(); + rcu_read_unlock(); + cond_resched(); + + rcu_read_lock(); + preempt_disable(); time_start = ktime_get_ns(); } } time_spent += ktime_get_ns() - time_start; + preempt_enable(); + rcu_read_unlock(); + do_div(time_spent, repeat); *time = time_spent > U32_MAX ? U32_MAX : (u32)time_spent; for_each_cgroup_storage_type(stype) bpf_cgroup_storage_free(storage[stype]); - return 0; + return ret; } static int bpf_test_finish(const union bpf_attr *kattr, -- cgit v1.2.3 From 11fe9262ed226c127f67ca4bd85977b22589b68a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= Date: Thu, 21 Feb 2019 13:07:38 +0100 Subject: Revert "xsk: simplify AF_XDP socket teardown" MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This reverts commit e2ce3674883ecba2605370404208c9d4a07ae1c3. It turns out that the sock destructor xsk_destruct was needed after all. The cleanup simplification broke the skb transmit cleanup path, due to that the umem was prematurely destroyed. The umem cannot be destroyed until all outstanding skbs are freed, which means that we cannot remove the umem until the sk_destruct has been called. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann --- net/xdp/xsk.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 45f3b528dc09..85e4fe4f18cc 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -366,7 +366,6 @@ static int xsk_release(struct socket *sock) xskq_destroy(xs->rx); xskq_destroy(xs->tx); - xdp_put_umem(xs->umem); sock_orphan(sk); sock->sk = NULL; @@ -718,6 +717,18 @@ static const struct proto_ops xsk_proto_ops = { .sendpage = sock_no_sendpage, }; +static void xsk_destruct(struct sock *sk) +{ + struct xdp_sock *xs = xdp_sk(sk); + + if (!sock_flag(sk, SOCK_DEAD)) + return; + + xdp_put_umem(xs->umem); + + sk_refcnt_debug_dec(sk); +} + static int xsk_create(struct net *net, struct socket *sock, int protocol, int kern) { @@ -744,6 +755,9 @@ static int xsk_create(struct net *net, struct socket *sock, int protocol, sk->sk_family = PF_XDP; + sk->sk_destruct = xsk_destruct; + sk_refcnt_debug_inc(sk); + sock_set_flag(sk, SOCK_RCU_FREE); xs = xdp_sk(sk); -- cgit v1.2.3