/* * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * This is where all NET/ROM frames pass, except for IP-over-NET/ROM which * cannot be fragmented in this manner. */ void nr_output(struct sock *sk, struct sk_buff *skb) { struct sk_buff *skbn; unsigned char transport[NR_TRANSPORT_LEN]; int err, frontlen, len; if (skb->len - NR_TRANSPORT_LEN > NR_MAX_PACKET_SIZE) { /* Save a copy of the Transport Header */ skb_copy_from_linear_data(skb, transport, NR_TRANSPORT_LEN); skb_pull(skb, NR_TRANSPORT_LEN); frontlen = skb_headroom(skb); while (skb->len > 0) { if ((skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err)) == NULL) return; skb_reserve(skbn, frontlen); len = (NR_MAX_PACKET_SIZE > skb->len) ? skb->len : NR_MAX_PACKET_SIZE; /* Copy the user data */ skb_copy_from_linear_data(skb, skb_put(skbn, len), len); skb_pull(skb, len); /* Duplicate the Transport Header */ skb_push(skbn, NR_TRANSPORT_LEN); skb_copy_to_linear_data(skbn, transport, NR_TRANSPORT_LEN); if (skb->len > 0) skbn->data[4] |= NR_MORE_FLAG; skb_queue_tail(&sk->sk_write_queue, skbn); /* Throw it on the queue */ } kfree_skb(skb); } else { skb_queue_tail(&sk->sk_write_queue, skb); /* Throw it on the queue */ } nr_kick(sk); } /* * This procedure is passed a buffer descriptor for an iframe. It builds * the rest of the control part of the frame and then writes it out. */ static void nr_send_iframe(struct sock *sk, struct sk_buff *skb) { struct nr_sock *nr = nr_sk(sk); if (skb == NULL) return; skb->data[2] = nr->vs; skb->data[3] = nr->vr; if (nr->condition & NR_COND_OWN_RX_BUSY) skb->data[4] |= NR_CHOKE_FLAG; nr_start_idletimer(sk); nr_transmit_buffer(sk, skb); } void nr_send_nak_frame(struct sock *sk) { struct sk_buff *skb, *skbn; struct nr_sock *nr = nr_sk(sk); if ((skb = skb_peek(&nr->ack_queue)) == NULL) return; if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) return; skbn->data[2] = nr->va; skbn->data[3] = nr->vr; if (nr->condition & NR_COND_OWN_RX_BUSY) skbn->data[4] |= NR_CHOKE_FLAG; nr_transmit_buffer(sk, skbn); nr->condition &= ~NR_COND_ACK_PENDING; nr->vl = nr->vr; nr_stop_t1timer(sk); } void nr_kick(struct sock *sk) { struct nr_sock *nr = nr_sk(sk); struct sk_buff *skb, *skbn; unsigned short start, end; if (nr->state != NR_STATE_3) return; if (nr->condition & NR_COND_PEER_RX_BUSY) return; if (!skb_peek(&sk->sk_write_queue)) return; start = (skb_peek(&nr->ack_queue) == NULL) ? nr->va : nr->vs; end = (nr->va + nr->window) % NR_MODULUS; if (start == end) return; nr->vs = start; /* * Transmit data until either we're out of data to send or * the window is full. */ /* * Dequeue the frame and copy it. */ skb = skb_dequeue(&sk->sk_write_queue); do { if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { skb_queue_head(&sk->sk_write_queue, skb); break; } skb_set_owner_w(skbn, sk); /* * Transmit the frame copy. */ nr_send_iframe(sk, skbn); nr->vs = (nr->vs + 1) % NR_MODULUS; /* * Requeue the original data frame. */ skb_queue_tail(&nr->ack_queue, skb); } while (nr->vs != end && (skb = skb_dequeue(&sk->sk_write_queue)) != NULL); nr->vl = nr->vr; nr->condition &= ~NR_COND_ACK_PENDING; if (!nr_t1timer_running(sk)) nr_start_t1timer(sk); } void nr_transmit_buffer(struct sock *sk, struct sk_buff *skb) { struct nr_sock *nr = nr_sk(sk); unsigned char *dptr; /* * Add the protocol byte and network header. */ dptr = skb_push(skb, NR_NETWORK_LEN); memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN); dptr[6] &= ~AX25_CBIT; dptr[6] &= ~AX25_EBIT; dptr[6] |= AX25_SSSID_SPARE; dptr += AX25_ADDR_LEN; memcpy(dptr, &nr->dest_addr, AX25_ADDR_LEN); dptr[6] &= ~AX25_CBIT; dptr[6] |= AX25_EBIT; dptr[6] |= AX25_SSSID_SPARE; dptr += AX25_ADDR_LEN; *dptr++ = sysctl_netrom_network_ttl_initialiser; if (!nr_route_frame(skb, NULL)) { kfree_skb(skb); nr_disconnect(sk, ENETUNREACH); } } /* * The following routines are taken from page 170 of the 7th ARRL Computer * Networking Conference paper, as is the whole state machine. */ void nr_establish_data_link(struct sock *sk) { struct nr_sock *nr = nr_sk(sk); nr->condition = 0x00; nr->n2count = 0; nr_write_internal(sk, NR_CONNREQ); nr_stop_t2timer(sk); nr_stop_t4timer(sk); nr_stop_idletimer(sk); nr_start_t1timer(sk); } /* * Never send a NAK when we are CHOKEd. */ void nr_enquiry_response(struct sock *sk) { struct nr_sock *nr = nr_sk(sk); int frametype = NR_INFOACK; if (nr->condition & NR_COND_OWN_RX_BUSY) { frametype |= NR_CHOKE_FLAG; } else { if (skb_peek(&nr->reseq_queue) != NULL) frametype |= NR_NAK_FLAG; } nr_write_internal(sk, frametype); nr->vl = nr->vr; nr->condition &= ~NR_COND_ACK_PENDING; } void nr_check_iframes_acked(struct sock *sk, unsigned short nr) { struct nr_sock *nrom = nr_sk(sk); if (nrom->vs == nr) { nr_frames_acked(sk, nr); nr_stop_t1timer(sk); nrom->n2count = 0; } else { if (nrom->va != nr) { nr_frames_acked(sk, nr); nr_start_t1timer(sk); } } } commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/net/ip6_route.h')