/* * X.25 Packet Layer release 002 * * This is ALPHA test software. This code may break your machine, randomly fail to work with new * releases, misbehave and/or generally screw up. It might even work. * * This code REQUIRES 2.1.15 or higher * * This module: * This module 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. * * History * X.25 001 Jonathan Naylor Started coding. * 2000-09-04 Henner Eisen Prevent freeing a dangling skb. */ #define pr_fmt(fmt) "X25: " fmt #include #include #include #include #include #include #include #include static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb) { struct sock *sk; unsigned short frametype; unsigned int lci; if (!pskb_may_pull(skb, X25_STD_MIN_LEN)) return 0; frametype = skb->data[2]; lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF); /* * LCI of zero is always for us, and its always a link control * frame. */ if (lci == 0) { x25_link_control(skb, nb, frametype); return 0; } /* * Find an existing socket. */ if ((sk = x25_find_socket(lci, nb)) != NULL) { int queued = 1; skb_reset_transport_header(skb); bh_lock_sock(sk); if (!sock_owned_by_user(sk)) { queued = x25_process_rx_frame(sk, skb); } else { queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf); } bh_unlock_sock(sk); sock_put(sk); return queued; } /* * Is is a Call Request ? if so process it. */ if (frametype == X25_CALL_REQUEST) return x25_rx_call_request(skb, nb, lci); /* * Its not a Call Request, nor is it a control frame. * Can we forward it? */ if (x25_forward_data(lci, nb, skb)) { if (frametype == X25_CLEAR_CONFIRMATION) { x25_clear_forward_by_lci(lci); } kfree_skb(skb); return 1; } /* x25_transmit_clear_request(nb, lci, 0x0D); */ if (frametype != X25_CLEAR_CONFIRMATION) pr_debug("x25_receive_data(): unknown frame type %2x\n",frametype); return 0; } int x25_lapb_receive_frame(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) { struct sk_buff *nskb; struct x25_neigh *nb; if (!net_eq(dev_net(dev), &init_net)) goto drop; nskb = skb_copy(skb, GFP_ATOMIC); if (!nskb) goto drop; kfree_skb(skb); skb = nskb; /* * Packet received from unrecognised device, throw it away. */ nb = x25_get_neigh(dev); if (!nb) { pr_debug("unknown neighbour - %s\n", dev->name); goto drop; } if (!pskb_may_pull(skb, 1)) return 0; switch (skb->data[0]) { case X25_IFACE_DATA: skb_pull(skb, 1); if (x25_receive_data(skb, nb)) { x25_neigh_put(nb); goto out; } break; case X25_IFACE_CONNECT: x25_link_established(nb); break; case X25_IFACE_DISCONNECT: x25_link_terminated(nb); break; } x25_neigh_put(nb); drop: kfree_skb(skb); out: return 0; } void x25_establish_link(struct x25_neigh *nb) { struct sk_buff *skb; unsigned char *ptr; switch (nb->dev->type) { case ARPHRD_X25: if ((skb = alloc_skb(1, GFP_ATOMIC)) == NULL) { pr_err("x25_dev: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = X25_IFACE_CONNECT; break; #if IS_ENABLED(CONFIG_LLC) case ARPHRD_ETHER: return; #endif default: return; } skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); } void x25_terminate_link(struct x25_neigh *nb) { struct sk_buff *skb; unsigned char *ptr; #if IS_ENABLED(CONFIG_LLC) if (nb->dev->type == ARPHRD_ETHER) return; #endif if (nb->dev->type != ARPHRD_X25) return; skb = alloc_skb(1, GFP_ATOMIC); if (!skb) { pr_err("x25_dev: out of memory\n"); return; } ptr = skb_put(skb, 1); *ptr = X25_IFACE_DISCONNECT; skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); } void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb) { unsigned char *dptr; skb_reset_network_header(skb); switch (nb->dev->type) { case ARPHRD_X25: dptr = skb_push(skb, 1); *dptr = X25_IFACE_DATA; break; #if IS_ENABLED(CONFIG_LLC) case ARPHRD_ETHER: kfree_skb(skb); return; #endif default: kfree_skb(skb); return; } skb->protocol = htons(ETH_P_X25); skb->dev = nb->dev; dev_queue_xmit(skb); } tat only
authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch)
tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /fs/xfs/libxfs/xfs_inode_fork.c
parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
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 'fs/xfs/libxfs/xfs_inode_fork.c')