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2022-05-02tcp: optimise skb_zerocopy_iter_stream()Pavel Begunkov
It's expensive to make a copy of 40B struct iov_iter to the point it was taking 0.2-0.5% of all cycles in my tests. iov_iter_revert() should be fine as it's a simple case without nested reverts/truncates. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a7e1690c00c5dfe700c30eb9a8a81ec59f6545dd.1650884401.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-30net: inline skb_zerocopy_iter_dgramPavel Begunkov
skb_zerocopy_iter_dgram() is a small proxy function, inline it. For that, move __zerocopy_sg_from_iter into linux/skbuff.h Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-04-27Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski
Daniel Borkmann says: ==================== pull-request: bpf-next 2022-04-27 We've added 85 non-merge commits during the last 18 day(s) which contain a total of 163 files changed, 4499 insertions(+), 1521 deletions(-). The main changes are: 1) Teach libbpf to enhance BPF verifier log with human-readable and relevant information about failed CO-RE relocations, from Andrii Nakryiko. 2) Add typed pointer support in BPF maps and enable it for unreferenced pointers (via probe read) and referenced ones that can be passed to in-kernel helpers, from Kumar Kartikeya Dwivedi. 3) Improve xsk to break NAPI loop when rx queue gets full to allow for forward progress to consume descriptors, from Maciej Fijalkowski & Björn Töpel. 4) Fix a small RCU read-side race in BPF_PROG_RUN routines which dereferenced the effective prog array before the rcu_read_lock, from Stanislav Fomichev. 5) Implement BPF atomic operations for RV64 JIT, and add libbpf parsing logic for USDT arguments under riscv{32,64}, from Pu Lehui. 6) Implement libbpf parsing of USDT arguments under aarch64, from Alan Maguire. 7) Enable bpftool build for musl and remove nftw with FTW_ACTIONRETVAL usage so it can be shipped under Alpine which is musl-based, from Dominique Martinet. 8) Clean up {sk,task,inode} local storage trace RCU handling as they do not need to use call_rcu_tasks_trace() barrier, from KP Singh. 9) Improve libbpf API documentation and fix error return handling of various API functions, from Grant Seltzer. 10) Enlarge offset check for bpf_skb_{load,store}_bytes() helpers given data length of frags + frag_list may surpass old offset limit, from Liu Jian. 11) Various improvements to prog_tests in area of logging, test execution and by-name subtest selection, from Mykola Lysenko. 12) Simplify map_btf_id generation for all map types by moving this process to build time with help of resolve_btfids infra, from Menglong Dong. 13) Fix a libbpf bug in probing when falling back to legacy bpf_probe_read*() helpers; the probing caused always to use old helpers, from Runqing Yang. 14) Add support for ARCompact and ARCv2 platforms for libbpf's PT_REGS tracing macros, from Vladimir Isaev. 15) Cleanup BPF selftests to remove old & unneeded rlimit code given kernel switched to memcg-based memory accouting a while ago, from Yafang Shao. 16) Refactor of BPF sysctl handlers to move them to BPF core, from Yan Zhu. 17) Fix BPF selftests in two occasions to work around regressions caused by latest LLVM to unblock CI until their fixes are worked out, from Yonghong Song. 18) Misc cleanups all over the place, from various others. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (85 commits) selftests/bpf: Add libbpf's log fixup logic selftests libbpf: Fix up verifier log for unguarded failed CO-RE relos libbpf: Simplify bpf_core_parse_spec() signature libbpf: Refactor CO-RE relo human description formatting routine libbpf: Record subprog-resolved CO-RE relocations unconditionally selftests/bpf: Add CO-RE relos and SEC("?...") to linked_funcs selftests libbpf: Avoid joining .BTF.ext data with BPF programs by section name libbpf: Fix logic for finding matching program for CO-RE relocation libbpf: Drop unhelpful "program too large" guess libbpf: Fix anonymous type check in CO-RE logic bpf: Compute map_btf_id during build time selftests/bpf: Add test for strict BTF type check selftests/bpf: Add verifier tests for kptr selftests/bpf: Add C tests for kptr libbpf: Add kptr type tag macros to bpf_helpers.h bpf: Make BTF type match stricter for release arguments bpf: Teach verifier about kptr_get kfunc helpers bpf: Wire up freeing of referenced kptr bpf: Populate pairs of btf_id and destructor kfunc in btf bpf: Adapt copy_map_value for multiple offset case ... ==================== Link: https://lore.kernel.org/r/20220427224758.20976-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-26net: generalize skb freeing deferral to per-cpu listsEric Dumazet
Logic added in commit f35f821935d8 ("tcp: defer skb freeing after socket lock is released") helped bulk TCP flows to move the cost of skbs frees outside of critical section where socket lock was held. But for RPC traffic, or hosts with RFS enabled, the solution is far from being ideal. For RPC traffic, recvmsg() has to return to user space right after skb payload has been consumed, meaning that BH handler has no chance to pick the skb before recvmsg() thread. This issue is more visible with BIG TCP, as more RPC fit one skb. For RFS, even if BH handler picks the skbs, they are still picked from the cpu on which user thread is running. Ideally, it is better to free the skbs (and associated page frags) on the cpu that originally allocated them. This patch removes the per socket anchor (sk->defer_list) and instead uses a per-cpu list, which will hold more skbs per round. This new per-cpu list is drained at the end of net_action_rx(), after incoming packets have been processed, to lower latencies. In normal conditions, skbs are added to the per-cpu list with no further action. In the (unlikely) cases where the cpu does not run net_action_rx() handler fast enough, we use an IPI to raise NET_RX_SOFTIRQ on the remote cpu. Also, we do not bother draining the per-cpu list from dev_cpu_dead() This is because skbs in this list have no requirement on how fast they should be freed. Note that we can add in the future a small per-cpu cache if we see any contention on sd->defer_lock. Tested on a pair of hosts with 100Gbit NIC, RFS enabled, and /proc/sys/net/ipv4/tcp_rmem[2] tuned to 16MB to work around page recycling strategy used by NIC driver (its page pool capacity being too small compared to number of skbs/pages held in sockets receive queues) Note that this tuning was only done to demonstrate worse conditions for skb freeing for this particular test. These conditions can happen in more general production workload. 10 runs of one TCP_STREAM flow Before: Average throughput: 49685 Mbit. Kernel profiles on cpu running user thread recvmsg() show high cost for skb freeing related functions (*) 57.81% [kernel] [k] copy_user_enhanced_fast_string (*) 12.87% [kernel] [k] skb_release_data (*) 4.25% [kernel] [k] __free_one_page (*) 3.57% [kernel] [k] __list_del_entry_valid 1.85% [kernel] [k] __netif_receive_skb_core 1.60% [kernel] [k] __skb_datagram_iter (*) 1.59% [kernel] [k] free_unref_page_commit (*) 1.16% [kernel] [k] __slab_free 1.16% [kernel] [k] _copy_to_iter (*) 1.01% [kernel] [k] kfree (*) 0.88% [kernel] [k] free_unref_page 0.57% [kernel] [k] ip6_rcv_core 0.55% [kernel] [k] ip6t_do_table 0.54% [kernel] [k] flush_smp_call_function_queue (*) 0.54% [kernel] [k] free_pcppages_bulk 0.51% [kernel] [k] llist_reverse_order 0.38% [kernel] [k] process_backlog (*) 0.38% [kernel] [k] free_pcp_prepare 0.37% [kernel] [k] tcp_recvmsg_locked (*) 0.37% [kernel] [k] __list_add_valid 0.34% [kernel] [k] sock_rfree 0.34% [kernel] [k] _raw_spin_lock_irq (*) 0.33% [kernel] [k] __page_cache_release 0.33% [kernel] [k] tcp_v6_rcv (*) 0.33% [kernel] [k] __put_page (*) 0.29% [kernel] [k] __mod_zone_page_state 0.27% [kernel] [k] _raw_spin_lock After patch: Average throughput: 73076 Mbit. Kernel profiles on cpu running user thread recvmsg() looks better: 81.35% [kernel] [k] copy_user_enhanced_fast_string 1.95% [kernel] [k] _copy_to_iter 1.95% [kernel] [k] __skb_datagram_iter 1.27% [kernel] [k] __netif_receive_skb_core 1.03% [kernel] [k] ip6t_do_table 0.60% [kernel] [k] sock_rfree 0.50% [kernel] [k] tcp_v6_rcv 0.47% [kernel] [k] ip6_rcv_core 0.45% [kernel] [k] read_tsc 0.44% [kernel] [k] _raw_spin_lock_irqsave 0.37% [kernel] [k] _raw_spin_lock 0.37% [kernel] [k] native_irq_return_iret 0.33% [kernel] [k] __inet6_lookup_established 0.31% [kernel] [k] ip6_protocol_deliver_rcu 0.29% [kernel] [k] tcp_rcv_established 0.29% [kernel] [k] llist_reverse_order v2: kdoc issue (kernel bots) do not defer if (alloc_cpu == smp_processor_id()) (Paolo) replace the sk_buff_head with a single-linked list (Jakub) add a READ_ONCE()/WRITE_ONCE() for the lockless read of sd->defer_list Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20220422201237.416238-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-04-20net: Change skb_ensure_writable()'s write_len param to unsigned int typeLiu Jian
Both pskb_may_pull() and skb_clone_writable()'s length parameters are of type unsigned int already. Therefore, change this function's write_len param to unsigned int type. Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220416105801.88708-3-liujian56@huawei.com
2022-04-01skbuff: fix coalescing for page_pool fragment recyclingJean-Philippe Brucker
Fix a use-after-free when using page_pool with page fragments. We encountered this problem during normal RX in the hns3 driver: (1) Initially we have three descriptors in the RX queue. The first one allocates PAGE1 through page_pool, and the other two allocate one half of PAGE2 each. Page references look like this: RX_BD1 _______ PAGE1 RX_BD2 _______ PAGE2 RX_BD3 _________/ (2) Handle RX on the first descriptor. Allocate SKB1, eventually added to the receive queue by tcp_queue_rcv(). (3) Handle RX on the second descriptor. Allocate SKB2 and pass it to netif_receive_skb(): netif_receive_skb(SKB2) ip_rcv(SKB2) SKB3 = skb_clone(SKB2) SKB2 and SKB3 share a reference to PAGE2 through skb_shinfo()->dataref. The other ref to PAGE2 is still held by RX_BD3: SKB2 ---+- PAGE2 SKB3 __/ / RX_BD3 _________/ (3b) Now while handling TCP, coalesce SKB3 with SKB1: tcp_v4_rcv(SKB3) tcp_try_coalesce(to=SKB1, from=SKB3) // succeeds kfree_skb_partial(SKB3) skb_release_data(SKB3) // drops one dataref SKB1 _____ PAGE1 \____ SKB2 _____ PAGE2 / RX_BD3 _________/ In skb_try_coalesce(), __skb_frag_ref() takes a page reference to PAGE2, where it should instead have increased the page_pool frag reference, pp_frag_count. Without coalescing, when releasing both SKB2 and SKB3, a single reference to PAGE2 would be dropped. Now when releasing SKB1 and SKB2, two references to PAGE2 will be dropped, resulting in underflow. (3c) Drop SKB2: af_packet_rcv(SKB2) consume_skb(SKB2) skb_release_data(SKB2) // drops second dataref page_pool_return_skb_page(PAGE2) // drops one pp_frag_count SKB1 _____ PAGE1 \____ PAGE2 / RX_BD3 _________/ (4) Userspace calls recvmsg() Copies SKB1 and releases it. Since SKB3 was coalesced with SKB1, we release the SKB3 page as well: tcp_eat_recv_skb(SKB1) skb_release_data(SKB1) page_pool_return_skb_page(PAGE1) page_pool_return_skb_page(PAGE2) // drops second pp_frag_count (5) PAGE2 is freed, but the third RX descriptor was still using it! In our case this causes IOMMU faults, but it would silently corrupt memory if the IOMMU was disabled. Change the logic that checks whether pp_recycle SKBs can be coalesced. We still reject differing pp_recycle between 'from' and 'to' SKBs, but in order to avoid the situation described above, we also reject coalescing when both 'from' and 'to' are pp_recycled and 'from' is cloned. The new logic allows coalescing a cloned pp_recycle SKB into a page refcounted one, because in this case the release (4) will drop the right reference, the one taken by skb_try_coalesce(). Fixes: 53e0961da1c7 ("page_pool: add frag page recycling support in page pool") Suggested-by: Alexander Duyck <alexanderduyck@fb.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Reviewed-by: Yunsheng Lin <linyunsheng@huawei.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-04net: skb: introduce the function kfree_skb_list_reason()Menglong Dong
To report reasons of skb drops, introduce the function kfree_skb_list_reason() and make kfree_skb_list() an inline call to it. This function will be used in the next commit in __dev_xmit_skb(). Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
net/batman-adv/hard-interface.c commit 690bb6fb64f5 ("batman-adv: Request iflink once in batadv-on-batadv check") commit 6ee3c393eeb7 ("batman-adv: Demote batadv-on-batadv skip error message") https://lore.kernel.org/all/20220302163049.101957-1-sw@simonwunderlich.de/ net/smc/af_smc.c commit 4d08b7b57ece ("net/smc: Fix cleanup when register ULP fails") commit 462791bbfa35 ("net/smc: add sysctl interface for SMC") https://lore.kernel.org/all/20220302112209.355def40@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-03-03net: Clear mono_delivery_time bit in __skb_tstamp_tx()Martin KaFai Lau
In __skb_tstamp_tx(), it may clone the egress skb and queues the clone to the sk_error_queue. The outgoing skb may have the mono delivery_time while the (rcv) timestamp is expected for the clone, so the skb->mono_delivery_time bit needs to be cleared from the clone. This patch adds the skb->mono_delivery_time clearing to the existing __net_timestamp() and use it in __skb_tstamp_tx(). The __net_timestamp() fast path usage in dev.c is changed to directly call ktime_get_real() since the mono_delivery_time bit is not set at that point. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-03net: Add skb_clear_tstamp() to keep the mono delivery_timeMartin KaFai Lau
Right now, skb->tstamp is reset to 0 whenever the skb is forwarded. If skb->tstamp has the mono delivery_time, clearing it can hurt the performance when it finally transmits out to fq@phy-dev. The earlier patch added a skb->mono_delivery_time bit to flag the skb->tstamp carrying the mono delivery_time. This patch adds skb_clear_tstamp() helper which keeps the mono delivery_time and clears everything else. The delivery_time clearing will be postponed until the stack knows the skb will be delivered locally. It will be done in a latter patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-03-02net: fix up skbs delta_truesize in UDP GRO frag_listlena wang
The truesize for a UDP GRO packet is added by main skb and skbs in main skb's frag_list: skb_gro_receive_list p->truesize += skb->truesize; The commit 53475c5dd856 ("net: fix use-after-free when UDP GRO with shared fraglist") introduced a truesize increase for frag_list skbs. When uncloning skb, it will call pskb_expand_head and trusesize for frag_list skbs may increase. This can occur when allocators uses __netdev_alloc_skb and not jump into __alloc_skb. This flow does not use ksize(len) to calculate truesize while pskb_expand_head uses. skb_segment_list err = skb_unclone(nskb, GFP_ATOMIC); pskb_expand_head if (!skb->sk || skb->destructor == sock_edemux) skb->truesize += size - osize; If we uses increased truesize adding as delta_truesize, it will be larger than before and even larger than previous total truesize value if skbs in frag_list are abundant. The main skb truesize will become smaller and even a minus value or a huge value for an unsigned int parameter. Then the following memory check will drop this abnormal skb. To avoid this error we should use the original truesize to segment the main skb. Fixes: 53475c5dd856 ("net: fix use-after-free when UDP GRO with shared fraglist") Signed-off-by: lena wang <lena.wang@mediatek.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/1646133431-8948-1-git-send-email-lena.wang@mediatek.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
tools/testing/selftests/net/mptcp/mptcp_join.sh 34aa6e3bccd8 ("selftests: mptcp: add ip mptcp wrappers") 857898eb4b28 ("selftests: mptcp: add missing join check") 6ef84b1517e0 ("selftests: mptcp: more robust signal race test") https://lore.kernel.org/all/20220221131842.468893-1-broonie@kernel.org/ drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/act.h drivers/net/ethernet/mellanox/mlx5/core/en/tc/act/ct.c fb7e76ea3f3b6 ("net/mlx5e: TC, Skip redundant ct clear actions") c63741b426e11 ("net/mlx5e: Fix MPLSoUDP encap to use MPLS action information") 09bf97923224f ("net/mlx5e: TC, Move pedit_headers_action to parse_attr") 84ba8062e383 ("net/mlx5e: Test CT and SAMPLE on flow attr") efe6f961cd2e ("net/mlx5e: CT, Don't set flow flag CT for ct clear flow") 3b49a7edec1d ("net/mlx5e: TC, Reject rules with multiple CT actions") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-22net: preserve skb_end_offset() in skb_unclone_keeptruesize()Eric Dumazet
syzbot found another way to trigger the infamous WARN_ON_ONCE(delta < len) in skb_try_coalesce() [1] I was able to root cause the issue to kfence. When kfence is in action, the following assertion is no longer true: int size = xxxx; void *ptr1 = kmalloc(size, gfp); void *ptr2 = kmalloc(size, gfp); if (ptr1 && ptr2) ASSERT(ksize(ptr1) == ksize(ptr2)); We attempted to fix these issues in the blamed commits, but forgot that TCP was possibly shifting data after skb_unclone_keeptruesize() has been used, notably from tcp_retrans_try_collapse(). So we not only need to keep same skb->truesize value, we also need to make sure TCP wont fill new tailroom that pskb_expand_head() was able to get from a addr = kmalloc(...) followed by ksize(addr) Split skb_unclone_keeptruesize() into two parts: 1) Inline skb_unclone_keeptruesize() for the common case, when skb is not cloned. 2) Out of line __skb_unclone_keeptruesize() for the 'slow path'. WARNING: CPU: 1 PID: 6490 at net/core/skbuff.c:5295 skb_try_coalesce+0x1235/0x1560 net/core/skbuff.c:5295 Modules linked in: CPU: 1 PID: 6490 Comm: syz-executor161 Not tainted 5.17.0-rc4-syzkaller-00229-g4f12b742eb2b #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:skb_try_coalesce+0x1235/0x1560 net/core/skbuff.c:5295 Code: bf 01 00 00 00 0f b7 c0 89 c6 89 44 24 20 e8 62 24 4e fa 8b 44 24 20 83 e8 01 0f 85 e5 f0 ff ff e9 87 f4 ff ff e8 cb 20 4e fa <0f> 0b e9 06 f9 ff ff e8 af b2 95 fa e9 69 f0 ff ff e8 95 b2 95 fa RSP: 0018:ffffc900063af268 EFLAGS: 00010293 RAX: 0000000000000000 RBX: 00000000ffffffd5 RCX: 0000000000000000 RDX: ffff88806fc05700 RSI: ffffffff872abd55 RDI: 0000000000000003 RBP: ffff88806e675500 R08: 00000000ffffffd5 R09: 0000000000000000 R10: ffffffff872ab659 R11: 0000000000000000 R12: ffff88806dd554e8 R13: ffff88806dd9bac0 R14: ffff88806dd9a2c0 R15: 0000000000000155 FS: 00007f18014f9700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020002000 CR3: 000000006be7a000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> tcp_try_coalesce net/ipv4/tcp_input.c:4651 [inline] tcp_try_coalesce+0x393/0x920 net/ipv4/tcp_input.c:4630 tcp_queue_rcv+0x8a/0x6e0 net/ipv4/tcp_input.c:4914 tcp_data_queue+0x11fd/0x4bb0 net/ipv4/tcp_input.c:5025 tcp_rcv_established+0x81e/0x1ff0 net/ipv4/tcp_input.c:5947 tcp_v4_do_rcv+0x65e/0x980 net/ipv4/tcp_ipv4.c:1719 sk_backlog_rcv include/net/sock.h:1037 [inline] __release_sock+0x134/0x3b0 net/core/sock.c:2779 release_sock+0x54/0x1b0 net/core/sock.c:3311 sk_wait_data+0x177/0x450 net/core/sock.c:2821 tcp_recvmsg_locked+0xe28/0x1fd0 net/ipv4/tcp.c:2457 tcp_recvmsg+0x137/0x610 net/ipv4/tcp.c:2572 inet_recvmsg+0x11b/0x5e0 net/ipv4/af_inet.c:850 sock_recvmsg_nosec net/socket.c:948 [inline] sock_recvmsg net/socket.c:966 [inline] sock_recvmsg net/socket.c:962 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2632 ___sys_recvmsg+0x127/0x200 net/socket.c:2674 __sys_recvmsg+0xe2/0x1a0 net/socket.c:2704 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: c4777efa751d ("net: add and use skb_unclone_keeptruesize() helper") Fixes: 097b9146c0e2 ("net: fix up truesize of cloned skb in skb_prepare_for_shift()") Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Marco Elver <elver@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-22net: add skb_set_end_offset() helperEric Dumazet
We have multiple places where this helper is convenient, and plan using it in the following patch. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-22net: __pskb_pull_tail() & pskb_carve_frag_list() drop_monitor friendsEric Dumazet
Whenever one of these functions pull all data from an skb in a frag_list, use consume_skb() instead of kfree_skb() to avoid polluting drop monitoring. Fixes: 6fa01ccd8830 ("skbuff: Add pskb_extract() helper function") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220220154052.1308469-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-18net-timestamp: convert sk->sk_tskey to atomic_tEric Dumazet
UDP sendmsg() can be lockless, this is causing all kinds of data races. This patch converts sk->sk_tskey to remove one of these races. BUG: KCSAN: data-race in __ip_append_data / __ip_append_data read to 0xffff8881035d4b6c of 4 bytes by task 8877 on cpu 1: __ip_append_data+0x1c1/0x1de0 net/ipv4/ip_output.c:994 ip_make_skb+0x13f/0x2d0 net/ipv4/ip_output.c:1636 udp_sendmsg+0x12bd/0x14c0 net/ipv4/udp.c:1249 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae write to 0xffff8881035d4b6c of 4 bytes by task 8880 on cpu 0: __ip_append_data+0x1d8/0x1de0 net/ipv4/ip_output.c:994 ip_make_skb+0x13f/0x2d0 net/ipv4/ip_output.c:1636 udp_sendmsg+0x12bd/0x14c0 net/ipv4/udp.c:1249 inet_sendmsg+0x5f/0x80 net/ipv4/af_inet.c:819 sock_sendmsg_nosec net/socket.c:705 [inline] sock_sendmsg net/socket.c:725 [inline] ____sys_sendmsg+0x39a/0x510 net/socket.c:2413 ___sys_sendmsg net/socket.c:2467 [inline] __sys_sendmmsg+0x267/0x4c0 net/socket.c:2553 __do_sys_sendmmsg net/socket.c:2582 [inline] __se_sys_sendmmsg net/socket.c:2579 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000054d -> 0x0000054e Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 8880 Comm: syz-executor.5 Not tainted 5.17.0-rc2-syzkaller-00167-gdcb85f85fa6f-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 09c2d251b707 ("net-timestamp: add key to disambiguate concurrent datagrams") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10skbuff: cleanup double word in commentTom Rix
Remove the second 'to'. Signed-off-by: Tom Rix <trix@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-01-09net: skb: introduce kfree_skb_reason()Menglong Dong
Introduce the interface kfree_skb_reason(), which is able to pass the reason why the skb is dropped to 'kfree_skb' tracepoint. Add the 'reason' field to 'trace_kfree_skb', therefor user can get more detail information about abnormal skb with 'drop_monitor' or eBPF. All drop reasons are defined in the enum 'skb_drop_reason', and they will be print as string in 'kfree_skb' tracepoint in format of 'reason: XXX'. ( Maybe the reasons should be defined in a uapi header file, so that user space can use them? ) Signed-off-by: Menglong Dong <imagedong@tencent.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-29Merge tag 'for-net-next-2021-12-29' of ↵Jakub Kicinski
git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next Luiz Augusto von Dentz says: ==================== bluetooth-next pull request for net-next: - Add support for Foxconn MT7922A - Add support for Realtek RTL8852AE - Rework HCI event handling to use skb_pull_data * tag 'for-net-next-2021-12-29' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next: (62 commits) Bluetooth: MGMT: Fix spelling mistake "simultanous" -> "simultaneous" Bluetooth: vhci: Set HCI_QUIRK_VALID_LE_STATES Bluetooth: MGMT: Fix LE simultaneous roles UUID if not supported Bluetooth: hci_sync: Add check simultaneous roles support Bluetooth: hci_sync: Wait for proper events when connecting LE Bluetooth: hci_sync: Add support for waiting specific LE subevents Bluetooth: hci_sync: Add hci_le_create_conn_sync Bluetooth: hci_event: Use skb_pull_data when processing inquiry results Bluetooth: hci_sync: Push sync command cancellation to workqueue Bluetooth: hci_qca: Stop IBS timer during BT OFF Bluetooth: btusb: Add support for Foxconn MT7922A Bluetooth: btintel: Add missing quirks and msft ext for legacy bootloader Bluetooth: btusb: Add two more Bluetooth parts for WCN6855 Bluetooth: L2CAP: Fix using wrong mode Bluetooth: hci_sync: Fix not always pausing advertising when necessary Bluetooth: mgmt: Make use of mgmt_send_event_skb in MGMT_EV_DEVICE_CONNECTED Bluetooth: mgmt: Make use of mgmt_send_event_skb in MGMT_EV_DEVICE_FOUND Bluetooth: mgmt: Introduce mgmt_alloc_skb and mgmt_send_event_skb Bluetooth: btusb: Return error code when getting patch status failed Bluetooth: btusb: Handle download_firmware failure cases ... ==================== Link: https://lore.kernel.org/r/20211229211258.2290966-1-luiz.dentz@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-16Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
No conflicts. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-12-16net: Fix double 0x prefix print in SKB dumpGal Pressman
When printing netdev features %pNF already takes care of the 0x prefix, remove the explicit one. Fixes: 6413139dfc64 ("skbuff: increase verbosity when dumping skb data") Signed-off-by: Gal Pressman <gal@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-12-07skbuff: introduce skb_pull_dataLuiz Augusto von Dentz
Like skb_pull but returns the original data pointer before pulling the data after performing a check against sbk->len. This allows to change code that does "struct foo *p = (void *)skb->data;" which is hard to audit and error prone, to: p = skb_pull_data(skb, sizeof(*p)); if (!p) return; Which is both safer and cleaner. Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
2021-11-22skbuff: Switch structure bounds to struct_group()Kees Cook
In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memcpy(), memmove(), and memset(), avoid intentionally writing across neighboring fields. Replace the existing empty member position markers "headers_start" and "headers_end" with a struct_group(). This will allow memcpy() and sizeof() to more easily reason about sizes, and improve readability. "pahole" shows no size nor member offset changes to struct sk_buff. "objdump -d" shows no object code changes (outside of WARNs affected by source line number changes). Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com> # drivers/net/wireguard/* Link: https://lore.kernel.org/lkml/20210728035006.GD35706@embeddedor Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-16net: gro: move skb_gro_receive into net/core/gro.cEric Dumazet
net/core/gro.c will contain all core gro functions, to shrink net/core/skbuff.c and net/core/dev.c Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-16net: gro: move skb_gro_receive_list to udp_offload.cEric Dumazet
This helper is used once, no need to keep it in fat net/core/skbuff.c Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-16net: move gro definitions to include/net/gro.hEric Dumazet
include/linux/netdevice.h became too big, move gro stuff into include/net/gro.h Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-16net: use sk_is_tcp() in more placesEric Dumazet
Move sk_is_tcp() to include/net/sock.h and use it where we can. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-03net: avoid double accounting for pure zerocopy skbsTalal Ahmad
Track skbs containing only zerocopy data and avoid charging them to kernel memory to correctly account the memory utilization for msg_zerocopy. All of the data in such skbs is held in user pages which are already accounted to user. Before this change, they are charged again in kernel in __zerocopy_sg_from_iter. The charging in kernel is excessive because data is not being copied into skb frags. This excessive charging can lead to kernel going into memory pressure state which impacts all sockets in the system adversely. Mark pure zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove charge/uncharge for data in such skbs. Initially, an skb is marked pure zerocopy when it is empty and in zerocopy path. skb can then change from a pure zerocopy skb to mixed data skb (zerocopy and copy data) if it is at tail of write queue and there is room available in it and non-zerocopy data is being sent in the next sendmsg call. At this time sk_mem_charge is done for the pure zerocopied data and the pure zerocopy flag is unmarked. We found that this happens very rarely on workloads that pass MSG_ZEROCOPY. A pure zerocopy skb can later be coalesced into normal skb if they are next to each other in queue but this patch prevents coalescing from happening. This avoids complexity of charging when skb downgrades from pure zerocopy to mixed. This is also rare. In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge for SKB_TRUESIZE(skb_end_offset(skb)) is done for sk_mem_charge in tcp_skb_entail for an skb without data. Testing with the msg_zerocopy.c benchmark between two hosts(100G nics) with zerocopy showed that before this patch the 'sock' variable in memory.stat for cgroup2 that tracks sum of sk_forward_alloc, sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this change it is 0. This is due to no charge to sk_forward_alloc for zerocopy data and shows memory utilization for kernel is lowered. With this commit we don't see the warning we saw in previous commit which resulted in commit 84882cf72cd774cf16fd338bdbf00f69ac9f9194. Signed-off-by: Talal Ahmad <talalahmad@google.com> Acked-by: Arjun Roy <arjunroy@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-02net: add and use skb_unclone_keeptruesize() helperEric Dumazet
While commit 097b9146c0e2 ("net: fix up truesize of cloned skb in skb_prepare_for_shift()") fixed immediate issues found when KFENCE was enabled/tested, there are still similar issues, when tcp_trim_head() hits KFENCE while the master skb is cloned. This happens under heavy networking TX workloads, when the TX completion might be delayed after incoming ACK. This patch fixes the WARNING in sk_stream_kill_queues when sk->sk_mem_queued/sk->sk_forward_alloc are not zero. Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Marco Elver <elver@google.com> Link: https://lore.kernel.org/r/20211102004555.1359210-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-01Revert "net: avoid double accounting for pure zerocopy skbs"Jakub Kicinski
This reverts commit f1a456f8f3fc5828d8abcad941860380ae147b1d. WARNING: CPU: 1 PID: 6819 at net/core/skbuff.c:5429 skb_try_coalesce+0x78b/0x7e0 CPU: 1 PID: 6819 Comm: xxxxxxx Kdump: loaded Tainted: G S 5.15.0-04194-gd852503f7711 #16 RIP: 0010:skb_try_coalesce+0x78b/0x7e0 Code: e8 2a bf 41 ff 44 8b b3 bc 00 00 00 48 8b 7c 24 30 e8 19 c0 41 ff 44 89 f0 48 03 83 c0 00 00 00 48 89 44 24 40 e9 47 fb ff ff <0f> 0b e9 ca fc ff ff 4c 8d 70 ff 48 83 c0 07 48 89 44 24 38 e9 61 RSP: 0018:ffff88881f449688 EFLAGS: 00010282 RAX: 00000000fffffe96 RBX: ffff8881566e4460 RCX: ffffffff82079f7e RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffff8881566e47b0 RBP: ffff8881566e46e0 R08: ffffed102619235d R09: ffffed102619235d R10: ffff888130c91ae3 R11: ffffed102619235c R12: ffff88881f4498a0 R13: 0000000000000056 R14: 0000000000000009 R15: ffff888130c91ac0 FS: 00007fec2cbb9700(0000) GS:ffff88881f440000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fec1b060d80 CR3: 00000003acf94005 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <IRQ> tcp_try_coalesce+0xeb/0x290 ? tcp_parse_options+0x610/0x610 ? mark_held_locks+0x79/0xa0 tcp_queue_rcv+0x69/0x2f0 tcp_rcv_established+0xa49/0xd40 ? tcp_data_queue+0x18a0/0x18a0 tcp_v6_do_rcv+0x1c9/0x880 ? rt6_mtu_change_route+0x100/0x100 tcp_v6_rcv+0x1624/0x1830 Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-01net: avoid double accounting for pure zerocopy skbsTalal Ahmad
Track skbs with only zerocopy data and avoid charging them to kernel memory to correctly account the memory utilization for msg_zerocopy. All of the data in such skbs is held in user pages which are already accounted to user. Before this change, they are charged again in kernel in __zerocopy_sg_from_iter. The charging in kernel is excessive because data is not being copied into skb frags. This excessive charging can lead to kernel going into memory pressure state which impacts all sockets in the system adversely. Mark pure zerocopy skbs with a SKBFL_PURE_ZEROCOPY flag and remove charge/uncharge for data in such skbs. Initially, an skb is marked pure zerocopy when it is empty and in zerocopy path. skb can then change from a pure zerocopy skb to mixed data skb (zerocopy and copy data) if it is at tail of write queue and there is room available in it and non-zerocopy data is being sent in the next sendmsg call. At this time sk_mem_charge is done for the pure zerocopied data and the pure zerocopy flag is unmarked. We found that this happens very rarely on workloads that pass MSG_ZEROCOPY. A pure zerocopy skb can later be coalesced into normal skb if they are next to each other in queue but this patch prevents coalescing from happening. This avoids complexity of charging when skb downgrades from pure zerocopy to mixed. This is also rare. In sk_wmem_free_skb, if it is a pure zerocopy skb, an sk_mem_uncharge for SKB_TRUESIZE(MAX_TCP_HEADER) is done for sk_mem_charge in tcp_skb_entail for an skb without data. Testing with the msg_zerocopy.c benchmark between two hosts(100G nics) with zerocopy showed that before this patch the 'sock' variable in memory.stat for cgroup2 that tracks sum of sk_forward_alloc, sk_rmem_alloc and sk_wmem_queued is around 1822720 and with this change it is 0. This is due to no charge to sk_forward_alloc for zerocopy data and shows memory utilization for kernel is lowered. Signed-off-by: Talal Ahmad <talalahmad@google.com> Acked-by: Arjun Roy <arjunroy@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-29mctp: Add flow extension to skbJeremy Kerr
This change adds a new skb extension for MCTP, to represent a request/response flow. The intention is to use this in a later change to allow i2c controllers to correctly configure a multiplexer over a flow. Since we have a cleanup function in the core path (if an extension is present), we'll need to make CONFIG_MCTP a bool, rather than a tristate. Includes a fix for a build warning with clang: Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-28Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
include/net/sock.h 7b50ecfcc6cd ("net: Rename ->stream_memory_read to ->sock_is_readable") 4c1e34c0dbff ("vsock: Enable y2038 safe timeval for timeout") drivers/net/ethernet/marvell/octeontx2/af/rvu_debugfs.c 0daa55d033b0 ("octeontx2-af: cn10k: debugfs for dumping LMTST map table") e77bcdd1f639 ("octeontx2-af: Display all enabled PF VF rsrc_alloc entries.") Adjacent code addition in both cases, keep both. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-10-22skb_expand_head() adjust skb->truesize incorrectlyVasily Averin
Christoph Paasch reports [1] about incorrect skb->truesize after skb_expand_head() call in ip6_xmit. This may happen because of two reasons: - skb_set_owner_w() for newly cloned skb is called too early, before pskb_expand_head() where truesize is adjusted for (!skb-sk) case. - pskb_expand_head() does not adjust truesize in (skb->sk) case. In this case sk->sk_wmem_alloc should be adjusted too. [1] https://lkml.org/lkml/2021/8/20/1082 Fixes: f1260ff15a71 ("skbuff: introduce skb_expand_head()") Fixes: 2d85a1b31dde ("ipv6: ip6_finish_output2: set sk into newly allocated nskb") Reported-by: Christoph Paasch <christoph.paasch@gmail.com> Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/644330dd-477e-0462-83bf-9f514c41edd1@virtuozzo.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-09-22skbuff: pass the result of data ksize to __build_skb_aroundLi RongQing
Avoid to call ksize again in __build_skb_around by passing the result of data ksize to __build_skb_around nginx stress test shows this change can reduce ksize cpu usage, and give a little performance boost Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-14skbuff: inline page_frag_alloc_align()Yajun Deng
The __alloc_frag_align() is short, and only called by two functions, so inline page_frag_alloc_align() for reduce the overhead of calls. Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-09-03skbuff: clean up inconsistent indentingColin Ian King
There is a statement that is indented one character too deeply, clean this up. Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-13net: in_irq() cleanupChangbin Du
Replace the obsolete and ambiguos macro in_irq() with new macro in_hardirq(). Signed-off-by: Changbin Du <changbin.du@gmail.com> Link: https://lore.kernel.org/r/20210813145749.86512-1-changbin.du@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-08-05net: fix GRO skb truesize updatePaolo Abeni
commit 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock reference") introduces a serious regression at the GRO layer setting the wrong truesize for stolen-head skbs. Restore the correct truesize: SKB_DATA_ALIGN(...) instead of SKB_TRUESIZE(...) Reported-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Fixes: 5e10da5385d2 ("skbuff: allow 'slow_gro' for skb carring sock reference") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Tested-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-03skbuff: introduce skb_expand_head()Vasily Averin
Like skb_realloc_headroom(), new helper increases headroom of specified skb. Unlike skb_realloc_headroom(), it does not allocate a new skb if possible; copies skb->sk on new skb when as needed and frees original skb in case of failures. This helps to simplify ip[6]_finish_output2() and a few other similar cases. Signed-off-by: Vasily Averin <vvs@virtuozzo.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-29skbuff: allow 'slow_gro' for skb carring sock referencePaolo Abeni
This change leverages the infrastructure introduced by the previous patches to allow soft devices passing to the GRO engine owned skbs without impacting the fast-path. It's up to the GRO caller ensuring the slow_gro bit validity before invoking the GRO engine. The new helper skb_prepare_for_gro() is introduced for that goal. On slow_gro, skbs are aggregated only with equal sk. Additionally, skb truesize on GRO recycle and free is correctly updated so that sk wmem is not changed by the GRO processing. rfc-> v1: - fixed bad truesize on dev_gro_receive NAPI_FREE - use the existing state bit Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-29net: optimize GRO for the common case.Paolo Abeni
After the previous patches, at GRO time, skb->slow_gro is usually 0, unless the packets comes from some H/W offload slowpath or tunnel. We can optimize the GRO code assuming !skb->slow_gro is likely. This remove multiple conditionals in the most common path, at the price of an additional one when we hit the above "slow-paths". Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-29sk_buff: track extension status in slow_groPaolo Abeni
Similar to the previous one, but tracking the active_extensions field status. Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-18net: Fix zero-copy head len calculation.Pravin B Shelar
In some cases skb head could be locked and entire header data is pulled from skb. When skb_zerocopy() called in such cases, following BUG is triggered. This patch fixes it by copying entire skb in such cases. This could be optimized incase this is performance bottleneck. ---8<--- kernel BUG at net/core/skbuff.c:2961! invalid opcode: 0000 [#1] SMP PTI CPU: 2 PID: 0 Comm: swapper/2 Tainted: G OE 5.4.0-77-generic #86-Ubuntu Hardware name: OpenStack Foundation OpenStack Nova, BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:skb_zerocopy+0x37a/0x3a0 RSP: 0018:ffffbcc70013ca38 EFLAGS: 00010246 Call Trace: <IRQ> queue_userspace_packet+0x2af/0x5e0 [openvswitch] ovs_dp_upcall+0x3d/0x60 [openvswitch] ovs_dp_process_packet+0x125/0x150 [openvswitch] ovs_vport_receive+0x77/0xd0 [openvswitch] netdev_port_receive+0x87/0x130 [openvswitch] netdev_frame_hook+0x4b/0x60 [openvswitch] __netif_receive_skb_core+0x2b4/0xc90 __netif_receive_skb_one_core+0x3f/0xa0 __netif_receive_skb+0x18/0x60 process_backlog+0xa9/0x160 net_rx_action+0x142/0x390 __do_softirq+0xe1/0x2d6 irq_exit+0xae/0xb0 do_IRQ+0x5a/0xf0 common_interrupt+0xf/0xf Code that triggered BUG: int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) { int i, j = 0; int plen = 0; /* length of skb->head fragment */ int ret; struct page *page; unsigned int offset; BUG_ON(!from->head_frag && !hlen); Signed-off-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-16skbuff: Fix a potential race while recycling page_pool packetsIlias Apalodimas
As Alexander points out, when we are trying to recycle a cloned/expanded SKB we might trigger a race. The recycling code relies on the pp_recycle bit to trigger, which we carry over to cloned SKBs. If that cloned SKB gets expanded or if we get references to the frags, call skb_release_data() and overwrite skb->head, we are creating separate instances accessing the same page frags. Since the skb_release_data() will first try to recycle the frags, there's a potential race between the original and cloned SKB, since both will have the pp_recycle bit set. Fix this by explicitly those SKBs not recyclable. The atomic_sub_return effectively limits us to a single release case, and when we are calling skb_release_data we are also releasing the option to perform the recycling, or releasing the pages from the page pool. Fixes: 6a5bcd84e886 ("page_pool: Allow drivers to hint on SKB recycling") Reported-by: Alexander Duyck <alexanderduyck@fb.com> Suggested-by: Alexander Duyck <alexanderduyck@fb.com> Reviewed-by: Alexander Duyck <alexanderduyck@fb.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-07-06skbuff: Release nfct refcount on napi stolen or re-used skbsPaul Blakey
When multiple SKBs are merged to a new skb under napi GRO, or SKB is re-used by napi, if nfct was set for them in the driver, it will not be released while freeing their stolen head state or on re-use. Release nfct on napi's stolen or re-used SKBs, and in gro_list_prepare, check conntrack metadata diff. Fixes: 5c6b94604744 ("net/mlx5e: CT: Handle misses after executing CT action") Reviewed-by: Roi Dayan <roid@nvidia.com> Signed-off-by: Paul Blakey <paulb@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-29net: sock: introduce sk_error_reportAlexander Aring
This patch introduces a function wrapper to call the sk_error_report callback. That will prepare to add additional handling whenever sk_error_report is called, for example to trace socket errors. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Trivial conflicts in net/can/isotp.c and tools/testing/selftests/net/mptcp/mptcp_connect.sh scaled_ppm_to_ppb() was moved from drivers/ptp/ptp_clock.c to include/linux/ptp_clock_kernel.h in -next so re-apply the fix there. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-06-10skbuff: fix incorrect msg_zerocopy copy notificationsWillem de Bruijn
msg_zerocopy signals if a send operation required copying with a flag in serr->ee.ee_code. This field can be incorrect as of the below commit, as a result of both structs uarg and serr pointing into the same skb->cb[]. uarg->zerocopy must be read before skb->cb[] is reinitialized to hold serr. Similar to other fields len, hi and lo, use a local variable to temporarily hold the value. This was not a problem before, when the value was passed as a function argument. Fixes: 75518851a2a0 ("skbuff: Push status and refcounts into sock_zerocopy_callback") Reported-by: Talal Ahmad <talalahmad@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Acked-by: Soheil Hassas Yeganeh <soheil@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-06-07page_pool: Allow drivers to hint on SKB recyclingIlias Apalodimas
Up to now several high speed NICs have custom mechanisms of recycling the allocated memory they use for their payloads. Our page_pool API already has recycling capabilities that are always used when we are running in 'XDP mode'. So let's tweak the API and the kernel network stack slightly and allow the recycling to happen even during the standard operation. The API doesn't take into account 'split page' policies used by those drivers currently, but can be extended once we have users for that. The idea is to be able to intercept the packet on skb_release_data(). If it's a buffer coming from our page_pool API recycle it back to the pool for further usage or just release the packet entirely. To achieve that we introduce a bit in struct sk_buff (pp_recycle:1) and a field in struct page (page->pp) to store the page_pool pointer. Storing the information in page->pp allows us to recycle both SKBs and their fragments. We could have skipped the skb bit entirely, since identical information can bederived from struct page. However, in an effort to affect the free path as less as possible, reading a single bit in the skb which is already in cache, is better that trying to derive identical information for the page stored data. The driver or page_pool has to take care of the sync operations on it's own during the buffer recycling since the buffer is, after opting-in to the recycling, never unmapped. Since the gain on the drivers depends on the architecture, we are not enabling recycling by default if the page_pool API is used on a driver. In order to enable recycling the driver must call skb_mark_for_recycle() to store the information we need for recycling in page->pp and enabling the recycling bit, or page_pool_store_mem_info() for a fragment. Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Co-developed-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Matteo Croce <mcroce@microsoft.com> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>