kernel/linux.git/include/net/xsk_buff_pool.h, branch v6.6.134

xsk: s/free_list_node/list_node/

2026-03-25T10:05:39+00:00

[ Upstream commit 30ec2c1baaead43903ad63ff8e3083949059083c ] Now that free_list_node's purpose is two-folded, make it just a 'list_node'. Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20241007122458.282590-3-maciej.fijalkowski@intel.com Stable-dep-of: f7387d6579d6 ("xsk: Fix zero-copy AF_XDP fragment drop") Signed-off-by: Sasha Levin

xsk: Get rid of xdp_buff_xsk::xskb_list_node

2026-03-25T10:05:39+00:00

[ Upstream commit b692bf9a7543af7ad11a59d182a3757578f0ba53 ] Let's bring xdp_buff_xsk back to occupying 2 cachelines by removing xskb_list_node - for the purpose of gathering the xskb frags free_list_node can be used, head of the list (xsk_buff_pool::xskb_list) stays as-is, just reuse the node ptr. It is safe to do as a single xdp_buff_xsk can never reside in two pool's lists simultaneously. Signed-off-by: Maciej Fijalkowski Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20241007122458.282590-2-maciej.fijalkowski@intel.com Stable-dep-of: f7387d6579d6 ("xsk: Fix zero-copy AF_XDP fragment drop") Signed-off-by: Sasha Levin

xsk: Fix race condition in AF_XDP generic RX path

2026-02-06T15:48:29+00:00

[ Upstream commit a1356ac7749cafc4e27aa62c0c4604b5dca4983e ] Move rx_lock from xsk_socket to xsk_buff_pool. Fix synchronization for shared umem mode in generic RX path where multiple sockets share single xsk_buff_pool. RX queue is exclusive to xsk_socket, while FILL queue can be shared between multiple sockets. This could result in race condition where two CPU cores access RX path of two different sockets sharing the same umem. Protect both queues by acquiring spinlock in shared xsk_buff_pool. Lock contention may be minimized in the future by some per-thread FQ buffering. It's safe and necessary to move spin_lock_bh(rx_lock) after xsk_rcv_check(): * xs->pool and spinlock_init is synchronized by xsk_bind() -> xsk_is_bound() memory barriers. * xsk_rcv_check() may return true at the moment of xsk_release() or xsk_unbind_dev(), however this will not cause any data races or race conditions. xsk_unbind_dev() removes xdp socket from all maps and waits for completion of all outstanding rx operations. Packets in RX path will either complete safely or drop. Signed-off-by: Eryk Kubanski Fixes: bf0bdd1343efb ("xdp: fix race on generic receive path") Acked-by: Magnus Karlsson Link: https://patch.msgid.link/20250416101908.10919-1-e.kubanski@partner.samsung.com Signed-off-by: Jakub Kicinski [ Conflict is resolved when backporting this fix. ] Signed-off-by: Jianqiang kang Signed-off-by: Greg Kroah-Hartman

xsk: support mbuf on ZC RX

2023-07-19T16:56:49+00:00

Given that skb_shared_info relies on skb_frag_t, in order to support xskb chaining, introduce xdp_buff_xsk::xskb_list_node and xsk_buff_pool::xskb_list. This is needed so ZC drivers can add frags as xskb nodes which will make it possible to handle it both when producing AF_XDP Rx descriptors as well as freeing/recycling all the frags that a single frame carries. Speaking of latter, update xsk_buff_free() to take care of list nodes. For the former (adding as frags), introduce xsk_buff_add_frag() for ZC drivers usage that is going to be used to add a frag to xskb list from pool. xsk_buff_get_frag() will be utilized by XDP_TX and, on contrary, will return xdp_buff. One of the previous patches added a wrapper for ZC Rx so implement xskb list walk and production of Rx descriptors there. On bind() path, bail out if socket wants to use ZC multi-buffer but underlying netdev does not support it. Signed-off-by: Maciej Fijalkowski Link: https://lore.kernel.org/r/20230719132421.584801-12-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov

xsk: allow core/drivers to test EOP bit

2023-07-19T16:56:49+00:00

Drivers are used to check for EOP bit whereas AF_XDP operates on inverted logic - user space indicates that current frag is not the last one and packet continues. For AF_XDP core needs, add xp_mb_desc() that will simply test XDP_PKT_CONTD from xdp_desc::options, but in order to preserve drivers default behavior, introduce an interface for ZC drivers that will negate xp_mb_desc() result and therefore make it easier to test EOP bit from during production of HW Tx descriptors. Signed-off-by: Maciej Fijalkowski Link: https://lore.kernel.org/r/20230719132421.584801-8-maciej.fijalkowski@intel.com Signed-off-by: Alexei Starovoitov

xsk: Use pool->dma_pages to check for DMA

2023-04-27T20:24:51+00:00

Compare pool->dma_pages instead of pool->dma_pages_cnt to check for an active DMA mapping. pool->dma_pages needs to be read anyway to access the map so this compiles to more efficient code. Signed-off-by: Kal Conley Signed-off-by: Daniel Borkmann Reviewed-by: Xuan Zhuo Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20230423180157.93559-1-kal.conley@dectris.com

xsk: Fix unaligned descriptor validation

2023-04-06T16:53:05+00:00

Make sure unaligned descriptors that straddle the end of the UMEM are considered invalid. Currently, descriptor validation is broken for zero-copy mode which only checks descriptors at page granularity. For example, descriptors in zero-copy mode that overrun the end of the UMEM but not a page boundary are (incorrectly) considered valid. The UMEM boundary check needs to happen before the page boundary and contiguity checks in xp_desc_crosses_non_contig_pg(). Do this check in xp_unaligned_validate_desc() instead like xp_check_unaligned() already does. Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API") Signed-off-by: Kal Conley Acked-by: Magnus Karlsson Link: https://lore.kernel.org/r/20230405235920.7305-2-kal.conley@dectris.com Signed-off-by: Martin KaFai Lau

xsk: Add cb area to struct xdp_buff_xsk

2023-01-23T17:58:23+00:00

Add an area after the xdp_buff in struct xdp_buff_xsk that drivers can use to stash extra information to use in metadata kfuncs. The maximum size of 24 bytes means the full xdp_buff_xsk structure will take up exactly two cache lines (with the cb field spanning both). Also add a macro drivers can use to check their own wrapping structs against the available size. Cc: John Fastabend Cc: David Ahern Cc: Martin KaFai Lau Cc: Jakub Kicinski Cc: Willem de Bruijn Cc: Jesper Dangaard Brouer Cc: Anatoly Burakov Cc: Alexander Lobakin Cc: Magnus Karlsson Cc: Maryam Tahhan Cc: xdp-hints@xdp-project.net Cc: netdev@vger.kernel.org Suggested-by: Jakub Kicinski Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20230119221536.3349901-15-sdf@google.com Signed-off-by: Martin KaFai Lau

xsk: Inherit need_wakeup flag for shared sockets

2022-09-22T15:16:22+00:00

The flag for need_wakeup is not set for xsks with `XDP_SHARED_UMEM` flag and of different queue ids and/or devices. They should inherit the flag from the first socket buffer pool since no flags can be specified once `XDP_SHARED_UMEM` is specified. Fixes: b5aea28dca134 ("xsk: Add shared umem support between queue ids") Signed-off-by: Jalal Mostafa Signed-off-by: Daniel Borkmann Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20220921135701.10199-1-jalal.a.mostapha@gmail.com

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