/* * Copyright (c) 2006 Oracle. All rights reserved. * * This software is available to you under a choice of one of two * licenses. You may choose to be licensed under the terms of the GNU * General Public License (GPL) Version 2, available from the file * COPYING in the main directory of this source tree, or the * OpenIB.org BSD license below: * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above * copyright notice, this list of conditions and the following * disclaimer. * * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials * provided with the distribution. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. * */ #include #include #include #include "rds_single_path.h" #include "rds.h" #include "loop.h" static DEFINE_SPINLOCK(loop_conns_lock); static LIST_HEAD(loop_conns); /* * This 'loopback' transport is a special case for flows that originate * and terminate on the same machine. * * Connection build-up notices if the destination address is thought of * as a local address by a transport. At that time it decides to use the * loopback transport instead of the bound transport of the sending socket. * * The loopback transport's sending path just hands the sent rds_message * straight to the receiving path via an embedded rds_incoming. */ /* * Usually a message transits both the sender and receiver's conns as it * flows to the receiver. In the loopback case, though, the receive path * is handed the sending conn so the sense of the addresses is reversed. */ static int rds_loop_xmit(struct rds_connection *conn, struct rds_message *rm, unsigned int hdr_off, unsigned int sg, unsigned int off) { struct scatterlist *sgp = &rm->data.op_sg[sg]; int ret = sizeof(struct rds_header) + be32_to_cpu(rm->m_inc.i_hdr.h_len); /* Do not send cong updates to loopback */ if (rm->m_inc.i_hdr.h_flags & RDS_FLAG_CONG_BITMAP) { rds_cong_map_updated(conn->c_fcong, ~(u64) 0); ret = min_t(int, ret, sgp->length - conn->c_xmit_data_off); goto out; } BUG_ON(hdr_off || sg || off); rds_inc_init(&rm->m_inc, conn, conn->c_laddr); /* For the embedded inc. Matching put is in loop_inc_free() */ rds_message_addref(rm); rds_recv_incoming(conn, conn->c_laddr, conn->c_faddr, &rm->m_inc, GFP_KERNEL); rds_send_drop_acked(conn, be64_to_cpu(rm->m_inc.i_hdr.h_sequence), NULL); rds_inc_put(&rm->m_inc); out: return ret; } /* * See rds_loop_xmit(). Since our inc is embedded in the rm, we * make sure the rm lives at least until the inc is done. */ static void rds_loop_inc_free(struct rds_incoming *inc) { struct rds_message *rm = container_of(inc, struct rds_message, m_inc); rds_message_put(rm); } /* we need to at least give the thread something to succeed */ static int rds_loop_recv_path(struct rds_conn_path *cp) { return 0; } struct rds_loop_connection { struct list_head loop_node; struct rds_connection *conn; }; /* * Even the loopback transport needs to keep track of its connections, * so it can call rds_conn_destroy() on them on exit. N.B. there are * 1+ loopback addresses (127.*.*.*) so it's not a bug to have * multiple loopback conns allocated, although rather useless. */ static int rds_loop_conn_alloc(struct rds_connection *conn, gfp_t gfp) { struct rds_loop_connection *lc; unsigned long flags; lc = kzalloc(sizeof(struct rds_loop_connection), gfp); if (!lc) return -ENOMEM; INIT_LIST_HEAD(&lc->loop_node); lc->conn = conn; conn->c_transport_data = lc; spin_lock_irqsave(&loop_conns_lock, flags); list_add_tail(&lc->loop_node, &loop_conns); spin_unlock_irqrestore(&loop_conns_lock, flags); return 0; } static void rds_loop_conn_free(void *arg) { struct rds_loop_connection *lc = arg; unsigned long flags; rdsdebug("lc %p\n", lc); spin_lock_irqsave(&loop_conns_lock, flags); list_del(&lc->loop_node); spin_unlock_irqrestore(&loop_conns_lock, flags); kfree(lc); } static int rds_loop_conn_path_connect(struct rds_conn_path *cp) { rds_connect_complete(cp->cp_conn); return 0; } static void rds_loop_conn_path_shutdown(struct rds_conn_path *cp) { } void rds_loop_exit(void) { struct rds_loop_connection *lc, *_lc; LIST_HEAD(tmp_list); /* avoid calling conn_destroy with irqs off */ spin_lock_irq(&loop_conns_lock); list_splice(&loop_conns, &tmp_list); INIT_LIST_HEAD(&loop_conns); spin_unlock_irq(&loop_conns_lock); list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) { WARN_ON(lc->conn->c_passive); rds_conn_destroy(lc->conn); } } /* * This is missing .xmit_* because loop doesn't go through generic * rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and * .laddr_check are missing because transport.c doesn't iterate over * rds_loop_transport. */ struct rds_transport rds_loop_transport = { .xmit = rds_loop_xmit, .recv_path = rds_loop_recv_path, .conn_alloc = rds_loop_conn_alloc, .conn_free = rds_loop_conn_free, .conn_path_connect = rds_loop_conn_path_connect, .conn_path_shutdown = rds_loop_conn_path_shutdown, .inc_copy_to_user = rds_message_inc_copy_to_user, .inc_free = rds_loop_inc_free, .t_name = "loopback", }; 96c543e55b6672d5a37e'>net/ipv6/inet6_hashtables.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 'net/ipv6/inet6_hashtables.c')