kernel/linux.git/include/net/gro_cells.h, branch v4.9.236

gro_cells: make sure device is up in gro_cells_receive()

2019-03-19T12:14:10+00:00

[ Upstream commit 2a5ff07a0eb945f291e361aa6f6becca8340ba46 ] We keep receiving syzbot reports [1] that show that tunnels do not play the rcu/IFF_UP rules properly. At device dismantle phase, gro_cells_destroy() will be called only after a full rcu grace period is observed after IFF_UP has been cleared. This means that IFF_UP needs to be tested before queueing packets into netif_rx() or gro_cells. This patch implements the test in gro_cells_receive() because too many callers do not seem to bother enough. [1] BUG: unable to handle kernel paging request at fffff4ca0b9ffffe PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.0.0+ #97 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:__skb_unlink include/linux/skbuff.h:1929 [inline] RIP: 0010:__skb_dequeue include/linux/skbuff.h:1945 [inline] RIP: 0010:__skb_queue_purge include/linux/skbuff.h:2656 [inline] RIP: 0010:gro_cells_destroy net/core/gro_cells.c:89 [inline] RIP: 0010:gro_cells_destroy+0x19d/0x360 net/core/gro_cells.c:78 Code: 03 42 80 3c 20 00 0f 85 53 01 00 00 48 8d 7a 08 49 8b 47 08 49 c7 07 00 00 00 00 48 89 f9 49 c7 47 08 00 00 00 00 48 c1 e9 03 <42> 80 3c 21 00 0f 85 10 01 00 00 48 89 c1 48 89 42 08 48 c1 e9 03 RSP: 0018:ffff8880aa3f79a8 EFLAGS: 00010a02 RAX: 00ffffffffffffe8 RBX: ffffe8ffffc64b70 RCX: 1ffff8ca0b9ffffe RDX: ffffc6505cffffe8 RSI: ffffffff858410ca RDI: ffffc6505cfffff0 RBP: ffff8880aa3f7a08 R08: ffff8880aa3e8580 R09: fffffbfff1263645 R10: fffffbfff1263644 R11: ffffffff8931b223 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffe8ffffc64b80 R15: ffffe8ffffc64b75 kobject: 'loop2' (000000004bd7d84a): kobject_uevent_env FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff4ca0b9ffffe CR3: 0000000094941000 CR4: 00000000001406f0 Call Trace: kobject: 'loop2' (000000004bd7d84a): fill_kobj_path: path = '/devices/virtual/block/loop2' ip_tunnel_dev_free+0x19/0x60 net/ipv4/ip_tunnel.c:1010 netdev_run_todo+0x51c/0x7d0 net/core/dev.c:8970 rtnl_unlock+0xe/0x10 net/core/rtnetlink.c:116 ip_tunnel_delete_nets+0x423/0x5f0 net/ipv4/ip_tunnel.c:1124 vti_exit_batch_net+0x23/0x30 net/ipv4/ip_vti.c:495 ops_exit_list.isra.0+0x105/0x160 net/core/net_namespace.c:156 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:551 process_one_work+0x98e/0x1790 kernel/workqueue.c:2173 worker_thread+0x98/0xe40 kernel/workqueue.c:2319 kthread+0x357/0x430 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Modules linked in: CR2: fffff4ca0b9ffffe [ end trace 513fc9c1338d1cb3 ] RIP: 0010:__skb_unlink include/linux/skbuff.h:1929 [inline] RIP: 0010:__skb_dequeue include/linux/skbuff.h:1945 [inline] RIP: 0010:__skb_queue_purge include/linux/skbuff.h:2656 [inline] RIP: 0010:gro_cells_destroy net/core/gro_cells.c:89 [inline] RIP: 0010:gro_cells_destroy+0x19d/0x360 net/core/gro_cells.c:78 Code: 03 42 80 3c 20 00 0f 85 53 01 00 00 48 8d 7a 08 49 8b 47 08 49 c7 07 00 00 00 00 48 89 f9 49 c7 47 08 00 00 00 00 48 c1 e9 03 <42> 80 3c 21 00 0f 85 10 01 00 00 48 89 c1 48 89 42 08 48 c1 e9 03 RSP: 0018:ffff8880aa3f79a8 EFLAGS: 00010a02 RAX: 00ffffffffffffe8 RBX: ffffe8ffffc64b70 RCX: 1ffff8ca0b9ffffe RDX: ffffc6505cffffe8 RSI: ffffffff858410ca RDI: ffffc6505cfffff0 RBP: ffff8880aa3f7a08 R08: ffff8880aa3e8580 R09: fffffbfff1263645 R10: fffffbfff1263644 R11: ffffffff8931b223 R12: dffffc0000000000 kobject: 'loop3' (00000000e4ee57a6): kobject_uevent_env R13: 0000000000000000 R14: ffffe8ffffc64b80 R15: ffffe8ffffc64b75 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffff4ca0b9ffffe CR3: 0000000094941000 CR4: 00000000001406f0 Fixes: c9e6bc644e55 ("net: add gro_cells infrastructure") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

gro_cell: add napi_disable in gro_cells_destroy

2019-01-09T15:16:41+00:00

[ Upstream commit 8e1da73acded4751a93d4166458a7e640f37d26c ] Add napi_disable routine in gro_cells_destroy since starting from commit c42858eaf492 ("gro_cells: remove spinlock protecting receive queues") gro_cell_poll and gro_cells_destroy can run concurrently on napi_skbs list producing a kernel Oops if the tunnel interface is removed while gro_cell_poll is running. The following Oops has been triggered removing a vxlan device while the interface is receiving traffic [ 5628.948853] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 [ 5628.949981] PGD 0 P4D 0 [ 5628.950308] Oops: 0002 [#1] SMP PTI [ 5628.950748] CPU: 0 PID: 9 Comm: ksoftirqd/0 Not tainted 4.20.0-rc6+ #41 [ 5628.952940] RIP: 0010:gro_cell_poll+0x49/0x80 [ 5628.955615] RSP: 0018:ffffc9000004fdd8 EFLAGS: 00010202 [ 5628.956250] RAX: 0000000000000000 RBX: ffffe8ffffc08150 RCX: 0000000000000000 [ 5628.957102] RDX: 0000000000000000 RSI: ffff88802356bf00 RDI: ffffe8ffffc08150 [ 5628.957940] RBP: 0000000000000026 R08: 0000000000000000 R09: 0000000000000000 [ 5628.958803] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000040 [ 5628.959661] R13: ffffe8ffffc08100 R14: 0000000000000000 R15: 0000000000000040 [ 5628.960682] FS: 0000000000000000(0000) GS:ffff88803ea00000(0000) knlGS:0000000000000000 [ 5628.961616] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5628.962359] CR2: 0000000000000008 CR3: 000000000221c000 CR4: 00000000000006b0 [ 5628.963188] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5628.964034] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5628.964871] Call Trace: [ 5628.965179] net_rx_action+0xf0/0x380 [ 5628.965637] __do_softirq+0xc7/0x431 [ 5628.966510] run_ksoftirqd+0x24/0x30 [ 5628.966957] smpboot_thread_fn+0xc5/0x160 [ 5628.967436] kthread+0x113/0x130 [ 5628.968283] ret_from_fork+0x3a/0x50 [ 5628.968721] Modules linked in: [ 5628.969099] CR2: 0000000000000008 [ 5628.969510] ---[ end trace 9d9dedc7181661fe ]--- [ 5628.970073] RIP: 0010:gro_cell_poll+0x49/0x80 [ 5628.972965] RSP: 0018:ffffc9000004fdd8 EFLAGS: 00010202 [ 5628.973611] RAX: 0000000000000000 RBX: ffffe8ffffc08150 RCX: 0000000000000000 [ 5628.974504] RDX: 0000000000000000 RSI: ffff88802356bf00 RDI: ffffe8ffffc08150 [ 5628.975462] RBP: 0000000000000026 R08: 0000000000000000 R09: 0000000000000000 [ 5628.976413] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000040 [ 5628.977375] R13: ffffe8ffffc08100 R14: 0000000000000000 R15: 0000000000000040 [ 5628.978296] FS: 0000000000000000(0000) GS:ffff88803ea00000(0000) knlGS:0000000000000000 [ 5628.979327] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5628.980044] CR2: 0000000000000008 CR3: 000000000221c000 CR4: 00000000000006b0 [ 5628.980929] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5628.981736] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5628.982409] Kernel panic - not syncing: Fatal exception in interrupt [ 5628.983307] Kernel Offset: disabled Fixes: c42858eaf492 ("gro_cells: remove spinlock protecting receive queues") Signed-off-by: Lorenzo Bianconi Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

gro_cells: mark napi struct as not busy poll candidates

2016-11-16T03:27:27+00:00

Rolf Neugebauer reported very long delays at netns dismantle. Eric W. Biederman was kind enough to look at this problem and noticed synchronize_net() occurring from netif_napi_del() that was added in linux-4.5 Busy polling makes no sense for tunnels NAPI. If busy poll is used for sessions over tunnels, the poller will need to poll the physical device queue anyway. netif_tx_napi_add() could be used here, but function name is misleading, and renaming it is not stable material, so set NAPI_STATE_NO_BUSY_POLL bit directly. This will avoid inserting gro_cells napi structures in napi_hash[] and avoid the problematic synchronize_net() (per possible cpu) that Rolf reported. Fixes: 93d05d4a320c ("net: provide generic busy polling to all NAPI drivers") Signed-off-by: Eric Dumazet Reported-by: Rolf Neugebauer Reported-by: Eric W. Biederman Acked-by: Cong Wang Tested-by: Rolf Neugebauer Signed-off-by: David S. Miller

gro_cells: gro_cells_receive now return error code

2016-07-22T04:50:41+00:00

so that the caller can update stats accordingly, if needed Signed-off-by: Paolo Abeni Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller

gro_cells: remove spinlock protecting receive queues

2015-08-31T22:17:17+00:00

As David pointed out, spinlock are no longer needed to protect the per cpu queues used in gro cells infrastructure. Also use new napi_complete_done() API so that gro_flush_timeout tweaks have an effect. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ip_tunnel: Create percpu gro_cell

2015-01-18T06:56:32+00:00

In the ipip tunnel, the skb->queue_mapping is lost in ipip_rcv(). All skb will be queued to the same cell->napi_skbs. The gro_cell_poll is pinned to one core under load. In production traffic, we also see severe rx_dropped in the tunl iface and it is probably due to this limit: skb_queue_len(&cell->napi_skbs) > netdev_max_backlog. This patch is trying to alloc_percpu(struct gro_cell) and schedule gro_cell_poll to process the skb in the same core. Signed-off-by: Martin KaFai Lau Acked-by: Eric Dumazet Signed-off-by: David S. Miller

gro: Fix kcalloc argument order

2013-01-28T03:46:33+00:00

First number, then size. Signed-off-by: Joe Perches Signed-off-by: David S. Miller

net: fix a race in gro_cell_poll()

2012-12-11T17:49:53+00:00

Dmitry Kravkov reported packet drops for GRE packets since GRO support was added. There is a race in gro_cell_poll() because we call napi_complete() without any synchronization with a concurrent gro_cells_receive() Once bug was triggered, we queued packets but did not schedule NAPI poll. We can fix this issue using the spinlock protected the napi_skbs queue, as we have to hold it to perform skb dequeue anyway. As we open-code skb_dequeue(), we no longer need to mask IRQS, as both producer and consumer run under BH context. Bug added in commit c9e6bc644e (net: add gro_cells infrastructure) Reported-by: Dmitry Kravkov Signed-off-by: Eric Dumazet Tested-by: Dmitry Kravkov Signed-off-by: David S. Miller

net: add gro_cells infrastructure

2012-10-01T21:01:46+00:00

This adds a new include file (include/net/gro_cells.h), to bring GRO (Generic Receive Offload) capability to tunnels, in a modular way. Because tunnels receive path is lockless, and GRO adds a serialization using a napi_struct, I chose to add an array of up to DEFAULT_MAX_NUM_RSS_QUEUES cells, so that multi queue devices wont be slowed down because of GRO layer. skb_get_rx_queue() is used as selector. In the future, we might add optional fanout capabilities, using rxhash for example. With help from Ben Hutchings who reminded me netif_get_num_default_rss_queues() function. Signed-off-by: Eric Dumazet Cc: Ben Hutchings Signed-off-by: David S. Miller