pm24.git/net/ipv4/tcp_minisocks.c, branch cpufreq-rust

tcp: Measure TIME-WAIT reuse delay with millisecond precision

2024-12-12T04:17:33Z

Prepare ground for TIME-WAIT socket reuse with subsecond delay. Today the last TS.Recent update timestamp, recorded in seconds and stored tp->ts_recent_stamp and tw->tw_ts_recent_stamp fields, has two purposes. Firstly, it is used to track the age of the last recorded TS.Recent value to detect when that value becomes outdated due to potential wrap-around of the other TCP timestamp clock (RFC 7323, section 5.5). For this purpose a second-based timestamp is completely sufficient as even in the worst case scenario of a peer using a high resolution microsecond timestamp, the wrap-around interval is ~36 minutes long. Secondly, it serves as a threshold value for allowing TIME-WAIT socket reuse. A TIME-WAIT socket can be reused only once the virtual 1 Hz clock, ktime_get_seconds, is past the TS.Recent update timestamp. The purpose behind delaying the TIME-WAIT socket reuse is to wait for the other TCP timestamp clock to tick at least once before reusing the connection. It is only then that the PAWS mechanism for the reopened connection can detect old duplicate segments from the previous connection incarnation (RFC 7323, appendix B.2). In this case using a timestamp with second resolution not only blocks the way toward allowing faster TIME-WAIT reuse after shorter subsecond delay, but also makes it impossible to reliably delay TW reuse by one second. As Eric Dumazet has pointed out [1], due to timestamp rounding, the TW reuse delay will actually be between (0, 1] seconds, and 0.5 seconds on average. We delay TW reuse for one full second only when last TS.Recent update coincides with our virtual 1 Hz clock tick. Considering the above, introduce a dedicated field to store a millisecond timestamp of transition into the TIME-WAIT state. Place it in an existing 4-byte hole inside inet_timewait_sock structure to avoid an additional memory cost. Use the new timestamp to (i) reliably delay TIME-WAIT reuse by one second, and (ii) prepare for configurable subsecond reuse delay in the subsequent change. We assume here that a full one second delay was the original intention in [2] because it accounts for the worst case scenario of the other TCP using the slowest recommended 1 Hz timestamp clock. A more involved alternative would be to change the resolution of the last TS.Recent update timestamp, tw->tw_ts_recent_stamp, to milliseconds. [1] https://lore.kernel.org/netdev/CANn89iKB4GFd8sVzCbRttqw_96o3i2wDhX-3DraQtsceNGYwug@mail.gmail.com/ [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b8439924316d5bcb266d165b93d632a4b4b859af Signed-off-by: Jakub Sitnicki Reviewed-by: Eric Dumazet Reviewed-by: Jason Xing Link: https://patch.msgid.link/20241209-jakub-krn-909-poc-msec-tw-tstamp-v2-1-66aca0eed03e@cloudflare.com Signed-off-by: Jakub Kicinski

tcp: populate XPS related fields of timewait sockets

2024-11-30T21:00:52Z

syzbot reported that netdev_core_pick_tx() was reading an uninitialized field [1]. This is indeed hapening for timewait sockets after recent commits. We can copy the original established socket sk_tx_queue_mapping and sk_rx_queue_mapping fields, instead of adding more checks in fast paths. As a bonus, packets will use the same transmit queue than prior ones, this potentially can avoid reordering. [1] BUG: KMSAN: uninit-value in netdev_pick_tx+0x5c7/0x1550 netdev_pick_tx+0x5c7/0x1550 netdev_core_pick_tx+0x1d2/0x4a0 net/core/dev.c:4312 __dev_queue_xmit+0x128a/0x57d0 net/core/dev.c:4394 dev_queue_xmit include/linux/netdevice.h:3168 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip_finish_output2+0x187c/0x1b70 net/ipv4/ip_output.c:236 __ip_finish_output+0x287/0x810 ip_finish_output+0x4b/0x600 net/ipv4/ip_output.c:324 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip_output+0x15f/0x3f0 net/ipv4/ip_output.c:434 dst_output include/net/dst.h:450 [inline] ip_local_out net/ipv4/ip_output.c:130 [inline] ip_send_skb net/ipv4/ip_output.c:1505 [inline] ip_push_pending_frames+0x444/0x570 net/ipv4/ip_output.c:1525 ip_send_unicast_reply+0x18c1/0x1b30 net/ipv4/ip_output.c:1672 tcp_v4_send_reset+0x238d/0x2a40 net/ipv4/tcp_ipv4.c:910 tcp_v4_rcv+0x48f8/0x5750 net/ipv4/tcp_ipv4.c:2431 ip_protocol_deliver_rcu+0x2a3/0x13d0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x336/0x500 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:578 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:628 [inline] ip_sublist_rcv+0x15f3/0x17f0 net/ipv4/ip_input.c:636 ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:670 __netif_receive_skb_list_ptype net/core/dev.c:5715 [inline] __netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5762 __netif_receive_skb_list net/core/dev.c:5814 [inline] netif_receive_skb_list_internal+0x1085/0x1700 net/core/dev.c:5905 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x3d4/0x810 net/core/dev.c:6256 virtqueue_napi_complete drivers/net/virtio_net.c:758 [inline] virtnet_poll+0x5d80/0x6bf0 drivers/net/virtio_net.c:3013 __napi_poll+0xe7/0x980 net/core/dev.c:6877 napi_poll net/core/dev.c:6946 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:7068 handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0x68/0x180 kernel/softirq.c:655 irq_exit_rcu+0x12/0x20 kernel/softirq.c:671 common_interrupt+0x97/0xb0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:693 __preempt_count_sub arch/x86/include/asm/preempt.h:84 [inline] kmsan_virt_addr_valid arch/x86/include/asm/kmsan.h:95 [inline] virt_to_page_or_null+0xfb/0x150 mm/kmsan/shadow.c:75 kmsan_get_metadata+0x13e/0x1c0 mm/kmsan/shadow.c:141 kmsan_get_shadow_origin_ptr+0x4d/0xb0 mm/kmsan/shadow.c:102 get_shadow_origin_ptr mm/kmsan/instrumentation.c:38 [inline] __msan_metadata_ptr_for_store_4+0x27/0x40 mm/kmsan/instrumentation.c:93 rcu_preempt_read_enter kernel/rcu/tree_plugin.h:390 [inline] __rcu_read_lock+0x46/0x70 kernel/rcu/tree_plugin.h:413 rcu_read_lock include/linux/rcupdate.h:847 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x114/0x19e0 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391 kthread+0x3e2/0x540 kernel/kthread.c:389 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 Uninit was created at: __alloc_pages_noprof+0x9a7/0xe00 mm/page_alloc.c:4774 alloc_pages_mpol_noprof+0x299/0x990 mm/mempolicy.c:2265 alloc_pages_noprof+0x1bf/0x1e0 mm/mempolicy.c:2344 alloc_slab_page mm/slub.c:2412 [inline] allocate_slab+0x320/0x12e0 mm/slub.c:2578 new_slab mm/slub.c:2631 [inline] ___slab_alloc+0x12ef/0x35e0 mm/slub.c:3818 __slab_alloc mm/slub.c:3908 [inline] __slab_alloc_node mm/slub.c:3961 [inline] slab_alloc_node mm/slub.c:4122 [inline] kmem_cache_alloc_noprof+0x57a/0xb20 mm/slub.c:4141 inet_twsk_alloc+0x11f/0x9d0 net/ipv4/inet_timewait_sock.c:188 tcp_time_wait+0x83/0xf50 net/ipv4/tcp_minisocks.c:309 tcp_rcv_state_process+0x145a/0x49d0 tcp_v4_do_rcv+0xbf9/0x11a0 net/ipv4/tcp_ipv4.c:1939 tcp_v4_rcv+0x51df/0x5750 net/ipv4/tcp_ipv4.c:2351 ip_protocol_deliver_rcu+0x2a3/0x13d0 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x336/0x500 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:578 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:628 [inline] ip_sublist_rcv+0x15f3/0x17f0 net/ipv4/ip_input.c:636 ip_list_rcv+0x9ef/0xa40 net/ipv4/ip_input.c:670 __netif_receive_skb_list_ptype net/core/dev.c:5715 [inline] __netif_receive_skb_list_core+0x15c5/0x1670 net/core/dev.c:5762 __netif_receive_skb_list net/core/dev.c:5814 [inline] netif_receive_skb_list_internal+0x1085/0x1700 net/core/dev.c:5905 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x3d4/0x810 net/core/dev.c:6256 virtqueue_napi_complete drivers/net/virtio_net.c:758 [inline] virtnet_poll+0x5d80/0x6bf0 drivers/net/virtio_net.c:3013 __napi_poll+0xe7/0x980 net/core/dev.c:6877 napi_poll net/core/dev.c:6946 [inline] net_rx_action+0xa5a/0x19b0 net/core/dev.c:7068 handle_softirqs+0x1a0/0x7c0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0x68/0x180 kernel/softirq.c:655 irq_exit_rcu+0x12/0x20 kernel/softirq.c:671 common_interrupt+0x97/0xb0 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x2b/0x40 arch/x86/include/asm/idtentry.h:693 CPU: 0 UID: 0 PID: 3962 Comm: kworker/u8:18 Not tainted 6.12.0-syzkaller-09073-g9f16d5e6f220 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: bat_events batadv_nc_worker Fixes: 79636038d37e ("ipv4: tcp: give socket pointer to control skbs") Fixes: 507a96737d99 ("ipv6: tcp: give socket pointer to control skbs") Reported-by: syzbot+8b0959fc16551d55896b@syzkaller.appspotmail.com Link: https://lore.kernel.org/netdev/674442bd.050a0220.1cc393.0072.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Reviewed-by: Kuniyuki Iwashima Reviewed-by: Brian Vazquez Link: https://patch.msgid.link/20241125093039.3095790-1-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: RX path for devmem TCP

2024-09-12T03:44:32Z

In tcp_recvmsg_locked(), detect if the skb being received by the user is a devmem skb. In this case - if the user provided the MSG_SOCK_DEVMEM flag - pass it to tcp_recvmsg_devmem() for custom handling. tcp_recvmsg_devmem() copies any data in the skb header to the linear buffer, and returns a cmsg to the user indicating the number of bytes returned in the linear buffer. tcp_recvmsg_devmem() then loops over the unaccessible devmem skb frags, and returns to the user a cmsg_devmem indicating the location of the data in the dmabuf device memory. cmsg_devmem contains this information: 1. the offset into the dmabuf where the payload starts. 'frag_offset'. 2. the size of the frag. 'frag_size'. 3. an opaque token 'frag_token' to return to the kernel when the buffer is to be released. The pages awaiting freeing are stored in the newly added sk->sk_user_frags, and each page passed to userspace is get_page()'d. This reference is dropped once the userspace indicates that it is done reading this page. All pages are released when the socket is destroyed. Signed-off-by: Willem de Bruijn Signed-off-by: Kaiyuan Zhang Signed-off-by: Mina Almasry Reviewed-by: Pavel Begunkov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20240910171458.219195-10-almasrymina@google.com Signed-off-by: Jakub Kicinski

tcp: annotate data-races around tcptw->tw_rcv_nxt

2024-08-29T00:08:17Z

No lock protects tcp tw fields. tcptw->tw_rcv_nxt can be changed from twsk_rcv_nxt_update() while other threads might read this field. Add READ_ONCE()/WRITE_ONCE() annotations, and make sure tcp_timewait_state_process() reads tcptw->tw_rcv_nxt only once. Signed-off-by: Eric Dumazet Reviewed-by: Jason Xing Link: https://patch.msgid.link/20240827015250.3509197-3-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: remove volatile qualifier on tw_substate

2024-08-29T00:08:16Z

Using a volatile qualifier for a specific struct field is unusual. Use instead READ_ONCE()/WRITE_ONCE() where necessary. tcp_timewait_state_process() can change tw_substate while other threads are reading this field. Signed-off-by: Eric Dumazet Reviewed-by: Jason Xing Link: https://patch.msgid.link/20240827015250.3509197-2-edumazet@google.com Signed-off-by: Jakub Kicinski

tcp: Don't access uninit tcp_rsk(req)->ao_keyid in tcp_create_openreq_child().

2024-07-16T09:56:14Z

syzkaller reported KMSAN splat in tcp_create_openreq_child(). [0] The uninit variable is tcp_rsk(req)->ao_keyid. tcp_rsk(req)->ao_keyid is initialised only when tcp_conn_request() finds a valid TCP AO option in SYN. Then, tcp_rsk(req)->used_tcp_ao is set accordingly. Let's not read tcp_rsk(req)->ao_keyid when tcp_rsk(req)->used_tcp_ao is false. [0]: BUG: KMSAN: uninit-value in tcp_create_openreq_child+0x198b/0x1ff0 net/ipv4/tcp_minisocks.c:610 tcp_create_openreq_child+0x198b/0x1ff0 net/ipv4/tcp_minisocks.c:610 tcp_v4_syn_recv_sock+0x18e/0x2170 net/ipv4/tcp_ipv4.c:1754 tcp_check_req+0x1a3e/0x20c0 net/ipv4/tcp_minisocks.c:852 tcp_v4_rcv+0x26a4/0x53a0 net/ipv4/tcp_ipv4.c:2265 ip_protocol_deliver_rcu+0x884/0x1270 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x30f/0x530 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x230/0x4c0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0x10f7/0x13e0 net/ipv4/ip_input.c:639 ip_list_rcv+0x952/0x9c0 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5703 [inline] __netif_receive_skb_list_core+0xd92/0x11d0 net/core/dev.c:5751 __netif_receive_skb_list net/core/dev.c:5803 [inline] netif_receive_skb_list_internal+0xd8f/0x1350 net/core/dev.c:5895 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x3f2/0x990 net/core/dev.c:6246 e1000_clean+0x1fa4/0x5e50 drivers/net/ethernet/intel/e1000/e1000_main.c:3808 __napi_poll+0xd9/0x990 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x90f/0x17e0 net/core/dev.c:6962 handle_softirqs+0x152/0x6b0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0x5d/0x120 kernel/softirq.c:649 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 __msan_instrument_asm_store+0xd6/0xe0 arch_atomic_inc arch/x86/include/asm/atomic.h:53 [inline] raw_atomic_inc include/linux/atomic/atomic-arch-fallback.h:992 [inline] atomic_inc include/linux/atomic/atomic-instrumented.h:436 [inline] page_ref_inc include/linux/page_ref.h:153 [inline] folio_ref_inc include/linux/page_ref.h:160 [inline] filemap_map_order0_folio mm/filemap.c:3596 [inline] filemap_map_pages+0x11c7/0x2270 mm/filemap.c:3644 do_fault_around mm/memory.c:4879 [inline] do_read_fault mm/memory.c:4912 [inline] do_fault mm/memory.c:5051 [inline] do_pte_missing mm/memory.c:3897 [inline] handle_pte_fault mm/memory.c:5381 [inline] __handle_mm_fault mm/memory.c:5524 [inline] handle_mm_fault+0x3677/0x6f00 mm/memory.c:5689 do_user_addr_fault+0x1373/0x2b20 arch/x86/mm/fault.c:1338 handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x54/0xc0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 Uninit was stored to memory at: tcp_create_openreq_child+0x1984/0x1ff0 net/ipv4/tcp_minisocks.c:611 tcp_v4_syn_recv_sock+0x18e/0x2170 net/ipv4/tcp_ipv4.c:1754 tcp_check_req+0x1a3e/0x20c0 net/ipv4/tcp_minisocks.c:852 tcp_v4_rcv+0x26a4/0x53a0 net/ipv4/tcp_ipv4.c:2265 ip_protocol_deliver_rcu+0x884/0x1270 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x30f/0x530 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x230/0x4c0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0x10f7/0x13e0 net/ipv4/ip_input.c:639 ip_list_rcv+0x952/0x9c0 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5703 [inline] __netif_receive_skb_list_core+0xd92/0x11d0 net/core/dev.c:5751 __netif_receive_skb_list net/core/dev.c:5803 [inline] netif_receive_skb_list_internal+0xd8f/0x1350 net/core/dev.c:5895 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x3f2/0x990 net/core/dev.c:6246 e1000_clean+0x1fa4/0x5e50 drivers/net/ethernet/intel/e1000/e1000_main.c:3808 __napi_poll+0xd9/0x990 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x90f/0x17e0 net/core/dev.c:6962 handle_softirqs+0x152/0x6b0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0x5d/0x120 kernel/softirq.c:649 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 Uninit was created at: __alloc_pages_noprof+0x82d/0xcb0 mm/page_alloc.c:4706 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page mm/slub.c:2265 [inline] allocate_slab mm/slub.c:2428 [inline] new_slab+0x2af/0x14e0 mm/slub.c:2481 ___slab_alloc+0xf73/0x3150 mm/slub.c:3667 __slab_alloc mm/slub.c:3757 [inline] __slab_alloc_node mm/slub.c:3810 [inline] slab_alloc_node mm/slub.c:3990 [inline] kmem_cache_alloc_noprof+0x53a/0x9f0 mm/slub.c:4009 reqsk_alloc_noprof net/ipv4/inet_connection_sock.c:920 [inline] inet_reqsk_alloc+0x63/0x700 net/ipv4/inet_connection_sock.c:951 tcp_conn_request+0x339/0x4860 net/ipv4/tcp_input.c:7177 tcp_v4_conn_request+0x13b/0x190 net/ipv4/tcp_ipv4.c:1719 tcp_rcv_state_process+0x2dd/0x4a10 net/ipv4/tcp_input.c:6711 tcp_v4_do_rcv+0xbee/0x10d0 net/ipv4/tcp_ipv4.c:1932 tcp_v4_rcv+0x3fad/0x53a0 net/ipv4/tcp_ipv4.c:2334 ip_protocol_deliver_rcu+0x884/0x1270 net/ipv4/ip_input.c:205 ip_local_deliver_finish+0x30f/0x530 net/ipv4/ip_input.c:233 NF_HOOK include/linux/netfilter.h:314 [inline] ip_local_deliver+0x230/0x4c0 net/ipv4/ip_input.c:254 dst_input include/net/dst.h:460 [inline] ip_sublist_rcv_finish net/ipv4/ip_input.c:580 [inline] ip_list_rcv_finish net/ipv4/ip_input.c:631 [inline] ip_sublist_rcv+0x10f7/0x13e0 net/ipv4/ip_input.c:639 ip_list_rcv+0x952/0x9c0 net/ipv4/ip_input.c:674 __netif_receive_skb_list_ptype net/core/dev.c:5703 [inline] __netif_receive_skb_list_core+0xd92/0x11d0 net/core/dev.c:5751 __netif_receive_skb_list net/core/dev.c:5803 [inline] netif_receive_skb_list_internal+0xd8f/0x1350 net/core/dev.c:5895 gro_normal_list include/net/gro.h:515 [inline] napi_complete_done+0x3f2/0x990 net/core/dev.c:6246 e1000_clean+0x1fa4/0x5e50 drivers/net/ethernet/intel/e1000/e1000_main.c:3808 __napi_poll+0xd9/0x990 net/core/dev.c:6771 napi_poll net/core/dev.c:6840 [inline] net_rx_action+0x90f/0x17e0 net/core/dev.c:6962 handle_softirqs+0x152/0x6b0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0x5d/0x120 kernel/softirq.c:649 common_interrupt+0x83/0x90 arch/x86/kernel/irq.c:278 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693 CPU: 0 PID: 239 Comm: modprobe Tainted: G B 6.10.0-rc7-01816-g852e42cc2dd4 #3 1107521f0c7b55c9309062382d0bda9f604dbb6d Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Reported-by: syzkaller Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://patch.msgid.link/20240714161719.6528-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni

net: tcp: un-pin the tw_timer

2024-06-10T10:54:18Z

After previous patch, even if timer fires immediately on another CPU, context that schedules the timer now holds the ehash spinlock, so timer cannot reap tw socket until ehash lock is released. BH disable is moved into hashdance_schedule. Signed-off-by: Florian Westphal Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

net: tcp/dccp: prepare for tw_timer un-pinning

2024-06-10T10:54:18Z

The TCP timewait timer is proving to be problematic for setups where scheduler CPU isolation is achieved at runtime via cpusets (as opposed to statically via isolcpus=domains). What happens there is a CPU goes through tcp_time_wait(), arming the time_wait timer, then gets isolated. TCP_TIMEWAIT_LEN later, the timer fires, causing interference for the now-isolated CPU. This is conceptually similar to the issue described in commit e02b93124855 ("workqueue: Unbind kworkers before sending them to exit()") Move inet_twsk_schedule() to within inet_twsk_hashdance(), with the ehash lock held. Expand the lock's critical section from inet_twsk_kill() to inet_twsk_deschedule_put(), serializing the scheduling vs descheduling of the timer. IOW, this prevents the following race: tcp_time_wait() inet_twsk_hashdance() inet_twsk_deschedule_put() del_timer_sync() inet_twsk_schedule() Thanks to Paolo Abeni for suggesting to leverage the ehash lock. This also restores a comment from commit ec94c2696f0b ("tcp/dccp: avoid one atomic operation for timewait hashdance") as inet_twsk_hashdance() had a "Step 1" and "Step 3" comment, but the "Step 2" had gone missing. inet_twsk_deschedule_put() now acquires the ehash spinlock to synchronize with inet_twsk_hashdance_schedule(). To ease possible regression search, actual un-pin is done in next patch. Link: https://lore.kernel.org/all/ZPhpfMjSiHVjQkTk@localhost.localdomain/ Reviewed-by: Eric Dumazet Signed-off-by: Valentin Schneider Co-developed-by: Florian Westphal Signed-off-by: Florian Westphal Signed-off-by: David S. Miller

tcp: annotate data-races around tw->tw_ts_recent and tw->tw_ts_recent_stamp

2024-06-05T11:30:09Z

These fields can be read and written locklessly, add annotations around these minor races. Signed-off-by: Eric Dumazet Reviewed-by: Simon Horman Signed-off-by: David S. Miller

tcp: reduce accepted window in NEW_SYN_RECV state

2024-05-27T23:47:23Z

Jason commit made checks against ACK sequence less strict and can be exploited by attackers to establish spoofed flows with less probes. Innocent users might use tcp_rmem[1] == 1,000,000,000, or something more reasonable. An attacker can use a regular TCP connection to learn the server initial tp->rcv_wnd, and use it to optimize the attack. If we make sure that only the announced window (smaller than 65535) is used for ACK validation, we force an attacker to use 65537 packets to complete the 3WHS (assuming server ISN is unknown) Fixes: 378979e94e95 ("tcp: remove 64 KByte limit for initial tp->rcv_wnd value") Link: https://datatracker.ietf.org/meeting/119/materials/slides-119-tcpm-ghost-acks-00 Signed-off-by: Eric Dumazet Acked-by: Neal Cardwell Reviewed-by: Jason Xing Link: https://lore.kernel.org/r/20240523130528.60376-1-edumazet@google.com Signed-off-by: Jakub Kicinski