kernel/git/stable/linux.git/net/xdp, branch linux-5.18.y

xsk: Clear page contiguity bit when unmapping pool

2022-07-12T14:42:21+00:00

[ Upstream commit 512d1999b8e94a5d43fba3afc73e774849674742 ] When a XSK pool gets mapped, xp_check_dma_contiguity() adds bit 0x1 to pages' DMA addresses that go in ascending order and at 4K stride. The problem is that the bit does not get cleared before doing unmap. As a result, a lot of warnings from iommu_dma_unmap_page() are seen in dmesg, which indicates that lookups by iommu_iova_to_phys() fail. Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API") Signed-off-by: Ivan Malov Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220628091848.534803-1-ivan.malov@oktetlabs.ru Signed-off-by: Sasha Levin

xsk: Fix generic transmit when completion queue reservation fails

2022-06-29T07:04:29+00:00

[ Upstream commit a6e944f25cdbe6b82275402b8bc9a55ad7aac10b ] Two points of potential failure in the generic transmit function are: 1. completion queue (cq) reservation failure. 2. skb allocation failure Originally the cq reservation was performed first, followed by the skb allocation. Commit 675716400da6 ("xdp: fix possible cq entry leak") reversed the order because at the time there was no mechanism available to undo the cq reservation which could have led to possible cq entry leaks in the event of skb allocation failure. However if the skb allocation is performed first and the cq reservation then fails, the xsk skb destructor is called which blindly adds the skb address to the already full cq leading to undefined behavior. This commit restores the original order (cq reservation followed by skb allocation) and uses the xskq_prod_cancel helper to undo the cq reserve in event of skb allocation failure. Fixes: 675716400da6 ("xdp: fix possible cq entry leak") Signed-off-by: Ciara Loftus Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220614070746.8871-1-ciara.loftus@intel.com Signed-off-by: Sasha Levin

xsk: Fix handling of invalid descriptors in XSK TX batching API

2022-06-14T16:45:06+00:00

[ Upstream commit d678cbd2f867a564a3c5b276c454e873f43f02f8 ] xdpxceiver run on a AF_XDP ZC enabled driver revealed a problem with XSK Tx batching API. There is a test that checks how invalid Tx descriptors are handled by AF_XDP. Each valid descriptor is followed by invalid one on Tx side whereas the Rx side expects only to receive a set of valid descriptors. In current xsk_tx_peek_release_desc_batch() function, the amount of available descriptors is hidden inside xskq_cons_peek_desc_batch(). This can be problematic in cases where invalid descriptors are present due to the fact that xskq_cons_peek_desc_batch() returns only a count of valid descriptors. This means that it is impossible to properly update XSK ring state when calling xskq_cons_release_n(). To address this issue, pull out the contents of xskq_cons_peek_desc_batch() so that callers (currently only xsk_tx_peek_release_desc_batch()) will always be able to update the state of ring properly, as total count of entries is now available and use this value as an argument in xskq_cons_release_n(). By doing so, xskq_cons_peek_desc_batch() can be dropped altogether. Fixes: 9349eb3a9d2a ("xsk: Introduce batched Tx descriptor interfaces") Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220607142200.576735-1-maciej.fijalkowski@intel.com Signed-off-by: Sasha Levin

xsk: Fix possible crash when multiple sockets are created

2022-04-26T14:19:54+00:00

Fix a crash that happens if an Rx only socket is created first, then a second socket is created that is Tx only and bound to the same umem as the first socket and also the same netdev and queue_id together with the XDP_SHARED_UMEM flag. In this specific case, the tx_descs array page pool was not created by the first socket as it was an Rx only socket. When the second socket is bound it needs this tx_descs array of this shared page pool as it has a Tx component, but unfortunately it was never allocated, leading to a crash. Note that this array is only used for zero-copy drivers using the batched Tx APIs, currently only ice and i40e. [ 5511.150360] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 5511.158419] #PF: supervisor write access in kernel mode [ 5511.164472] #PF: error_code(0x0002) - not-present page [ 5511.170416] PGD 0 P4D 0 [ 5511.173347] Oops: 0002 [#1] PREEMPT SMP PTI [ 5511.178186] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G E 5.18.0-rc1+ #97 [ 5511.187245] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 [ 5511.198418] RIP: 0010:xsk_tx_peek_release_desc_batch+0x198/0x310 [ 5511.205375] Code: c0 83 c6 01 84 c2 74 6d 8d 46 ff 23 07 44 89 e1 48 83 c0 14 48 c1 e1 04 48 c1 e0 04 48 03 47 10 4c 01 c1 48 8b 50 08 48 8b 00 <48> 89 51 08 48 89 01 41 80 bd d7 00 00 00 00 75 82 48 8b 19 49 8b [ 5511.227091] RSP: 0018:ffffc90000003dd0 EFLAGS: 00010246 [ 5511.233135] RAX: 0000000000000000 RBX: ffff88810c8da600 RCX: 0000000000000000 [ 5511.241384] RDX: 000000000000003c RSI: 0000000000000001 RDI: ffff888115f555c0 [ 5511.249634] RBP: ffffc90000003e08 R08: 0000000000000000 R09: ffff889092296b48 [ 5511.257886] R10: 0000ffffffffffff R11: ffff889092296800 R12: 0000000000000000 [ 5511.266138] R13: ffff88810c8db500 R14: 0000000000000040 R15: 0000000000000100 [ 5511.274387] FS: 0000000000000000(0000) GS:ffff88903f800000(0000) knlGS:0000000000000000 [ 5511.283746] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5511.290389] CR2: 0000000000000008 CR3: 00000001046e2001 CR4: 00000000003706f0 [ 5511.298640] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 5511.306892] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 5511.315142] Call Trace: [ 5511.317972] [ 5511.320301] ice_xmit_zc+0x68/0x2f0 [ice] [ 5511.324977] ? ktime_get+0x38/0xa0 [ 5511.328913] ice_napi_poll+0x7a/0x6a0 [ice] [ 5511.333784] __napi_poll+0x2c/0x160 [ 5511.337821] net_rx_action+0xdd/0x200 [ 5511.342058] __do_softirq+0xe6/0x2dd [ 5511.346198] irq_exit_rcu+0xb5/0x100 [ 5511.350339] common_interrupt+0xa4/0xc0 [ 5511.354777] [ 5511.357201] [ 5511.359625] asm_common_interrupt+0x1e/0x40 [ 5511.364466] RIP: 0010:cpuidle_enter_state+0xd2/0x360 [ 5511.370211] Code: 49 89 c5 0f 1f 44 00 00 31 ff e8 e9 00 7b ff 45 84 ff 74 12 9c 58 f6 c4 02 0f 85 72 02 00 00 31 ff e8 02 0c 80 ff fb 45 85 f6 <0f> 88 11 01 00 00 49 63 c6 4c 2b 2c 24 48 8d 14 40 48 8d 14 90 49 [ 5511.391921] RSP: 0018:ffffffff82a03e60 EFLAGS: 00000202 [ 5511.397962] RAX: ffff88903f800000 RBX: 0000000000000001 RCX: 000000000000001f [ 5511.406214] RDX: 0000000000000000 RSI: ffffffff823400b9 RDI: ffffffff8234c046 [ 5511.424646] RBP: ffff88810a384800 R08: 000005032a28c046 R09: 0000000000000008 [ 5511.443233] R10: 000000000000000b R11: 0000000000000006 R12: ffffffff82bcf700 [ 5511.461922] R13: 000005032a28c046 R14: 0000000000000001 R15: 0000000000000000 [ 5511.480300] cpuidle_enter+0x29/0x40 [ 5511.494329] do_idle+0x1c7/0x250 [ 5511.507610] cpu_startup_entry+0x19/0x20 [ 5511.521394] start_kernel+0x649/0x66e [ 5511.534626] secondary_startup_64_no_verify+0xc3/0xcb [ 5511.549230] Detect such case during bind() and allocate this memory region via newly introduced xp_alloc_tx_descs(). Also, use kvcalloc instead of kcalloc as for other buffer pool allocations, so that it matches the kvfree() from xp_destroy(). Fixes: d1bc532e99be ("i40e: xsk: Move tmp desc array from driver to pool") Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220425153745.481322-1-maciej.fijalkowski@intel.com

xsk: Fix l2fwd for copy mode + busy poll combo

2022-04-07T21:09:08+00:00

While checking AF_XDP copy mode combined with busy poll, strange results were observed. rxdrop and txonly scenarios worked fine, but l2fwd broke immediately. After a deeper look, it turned out that for l2fwd, Tx side was exiting early due to xsk_no_wakeup() returning true and in the end xsk_generic_xmit() was never called. Note that AF_XDP Tx in copy mode is syscall steered, so the current behavior is broken. Txonly scenario only worked due to the fact that sk_mark_napi_id_once_xdp() was never called - since Rx side is not in the picture for this case and mentioned function is called in xsk_rcv_check(), sk::sk_napi_id was never set, which in turn meant that xsk_no_wakeup() was returning false (see the sk->sk_napi_id >= MIN_NAPI_ID check in there). To fix this, prefer busy poll in xsk_sendmsg() only when zero copy is enabled on a given AF_XDP socket. By doing so, busy poll in copy mode would not exit early on Tx side and eventually xsk_generic_xmit() will be called. Fixes: a0731952d9cd ("xsk: Add busy-poll support for {recv,send}msg()") Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220406155804.434493-1-maciej.fijalkowski@intel.com

xsk: Do not write NULL in SW ring at allocation failure

2022-03-29T02:56:28+00:00

For the case when xp_alloc_batch() is used but the batched allocation cannot be used, there is a slow path that uses the non-batched xp_alloc(). When it fails to allocate an entry, it returns NULL. The current code wrote this NULL into the entry of the provided results array (pointer to the driver SW ring usually) and returned. This might not be what the driver expects and to make things simpler, just write successfully allocated xdp_buffs into the SW ring,. The driver might have information in there that is still important after an allocation failure. Note that at this point in time, there are no drivers using xp_alloc_batch() that could trigger this slow path. But one might get added. Fixes: 47e4075df300 ("xsk: Batched buffer allocation for the pool") Signed-off-by: Magnus Karlsson Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220328142123.170157-2-maciej.fijalkowski@intel.com

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-03-23T17:53:49+00:00

Merge in overtime fixes, no conflicts. Signed-off-by: Jakub Kicinski

xsk: Fix race at socket teardown

2022-02-28T14:39:53+00:00

Fix a race in the xsk socket teardown code that can lead to a NULL pointer dereference splat. The current xsk unbind code in xsk_unbind_dev() starts by setting xs->state to XSK_UNBOUND, sets xs->dev to NULL and then waits for any NAPI processing to terminate using synchronize_net(). After that, the release code starts to tear down the socket state and free allocated memory. BUG: kernel NULL pointer dereference, address: 00000000000000c0 PGD 8000000932469067 P4D 8000000932469067 PUD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 25 PID: 69132 Comm: grpcpp_sync_ser Tainted: G I 5.16.0+ #2 Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.2.10 03/09/2015 RIP: 0010:__xsk_sendmsg+0x2c/0x690 [...] RSP: 0018:ffffa2348bd13d50 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000040 RCX: ffff8d5fc632d258 RDX: 0000000000400000 RSI: ffffa2348bd13e10 RDI: ffff8d5fc5489800 RBP: ffffa2348bd13db0 R08: 0000000000000000 R09: 00007ffffffff000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8d5fc5489800 R13: ffff8d5fcb0f5140 R14: ffff8d5fcb0f5140 R15: 0000000000000000 FS: 00007f991cff9400(0000) GS:ffff8d6f1f700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 0000000114888005 CR4: 00000000001706e0 Call Trace: ? aa_sk_perm+0x43/0x1b0 xsk_sendmsg+0xf0/0x110 sock_sendmsg+0x65/0x70 __sys_sendto+0x113/0x190 ? debug_smp_processor_id+0x17/0x20 ? fpregs_assert_state_consistent+0x23/0x50 ? exit_to_user_mode_prepare+0xa5/0x1d0 __x64_sys_sendto+0x29/0x30 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae There are two problems with the current code. First, setting xs->dev to NULL before waiting for all users to stop using the socket is not correct. The entry to the data plane functions xsk_poll(), xsk_sendmsg(), and xsk_recvmsg() are all guarded by a test that xs->state is in the state XSK_BOUND and if not, it returns right away. But one process might have passed this test but still have not gotten to the point in which it uses xs->dev in the code. In this interim, a second process executing xsk_unbind_dev() might have set xs->dev to NULL which will lead to a crash for the first process. The solution here is just to get rid of this NULL assignment since it is not used anymore. Before commit 42fddcc7c64b ("xsk: use state member for socket synchronization"), xs->dev was the gatekeeper to admit processes into the data plane functions, but it was replaced with the state variable xs->state in the aforementioned commit. The second problem is that synchronize_net() does not wait for any process in xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() to complete, which means that the state they rely on might be cleaned up prematurely. This can happen when the notifier gets called (at driver unload for example) as it uses xsk_unbind_dev(). Solve this by extending the RCU critical region from just the ndo_xsk_wakeup to the whole functions mentioned above, so that both the test of xs->state == XSK_BOUND and the last use of any member of xs is covered by the RCU critical section. This will guarantee that when synchronize_net() completes, there will be no processes left executing xsk_poll(), xsk_sendmsg(), or xsk_recvmsg() and state can be cleaned up safely. Note that we need to drop the RCU lock for the skb xmit path as it uses functions that might sleep. Due to this, we have to retest the xs->state after we grab the mutex that protects the skb xmit code from, among a number of things, an xsk_unbind_dev() being executed from the notifier at the same time. Fixes: 42fddcc7c64b ("xsk: use state member for socket synchronization") Reported-by: Elza Mathew Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20220228094552.10134-1-magnus.karlsson@gmail.com

i40e: xsk: Move tmp desc array from driver to pool

2022-01-27T16:25:32+00:00

Move desc_array from the driver to the pool. The reason behind this is that we can then reuse this array as a temporary storage for descriptors in all zero-copy drivers that use the batched interface. This will make it easier to add batching to more drivers. i40e is the only driver that has a batched Tx zero-copy implementation, so no need to touch any other driver. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Reviewed-by: Alexander Lobakin Link: https://lore.kernel.org/bpf/20220125160446.78976-6-maciej.fijalkowski@intel.com

bpf: remove unused static inlines

2022-01-27T05:17:53+00:00

Remove two dead stubs, sk_msg_clear_meta() was never used, use of xskq_cons_is_full() got replaced by xsk_tx_writeable() in v5.10. Signed-off-by: Jakub Kicinski Link: https://lore.kernel.org/r/20220126185412.2776254-1-kuba@kernel.org Signed-off-by: Alexei Starovoitov