1. 08 Oct, 2024 14 commits
  2. 07 Oct, 2024 4 commits
  3. 04 Oct, 2024 14 commits
    • Christophe JAILLET's avatar
      net: phy: bcm84881: Fix some error handling paths · 9234a254
      Christophe JAILLET authored
      If phy_read_mmd() fails, the error code stored in 'bmsr' should be returned
      instead of 'val' which is likely to be 0.
      
      Fixes: 75f4d8d1 ("net: phy: add Broadcom BCM84881 PHY driver")
      Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
      Link: https://patch.msgid.link/3e1755b0c40340d00e089d6adae5bca2f8c79e53.1727982168.git.christophe.jaillet@wanadoo.frSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      9234a254
    • Anastasia Kovaleva's avatar
      net: Fix an unsafe loop on the list · 1dae9f11
      Anastasia Kovaleva authored
      The kernel may crash when deleting a genetlink family if there are still
      listeners for that family:
      
      Oops: Kernel access of bad area, sig: 11 [#1]
        ...
        NIP [c000000000c080bc] netlink_update_socket_mc+0x3c/0xc0
        LR [c000000000c0f764] __netlink_clear_multicast_users+0x74/0xc0
        Call Trace:
      __netlink_clear_multicast_users+0x74/0xc0
      genl_unregister_family+0xd4/0x2d0
      
      Change the unsafe loop on the list to a safe one, because inside the
      loop there is an element removal from this list.
      
      Fixes: b8273570 ("genetlink: fix netns vs. netlink table locking (2)")
      Cc: stable@vger.kernel.org
      Signed-off-by: default avatarAnastasia Kovaleva <a.kovaleva@yadro.com>
      Reviewed-by: default avatarDmitry Bogdanov <d.bogdanov@yadro.com>
      Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
      Link: https://patch.msgid.link/20241003104431.12391-1-a.kovaleva@yadro.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      1dae9f11
    • Luiz Augusto von Dentz's avatar
      Bluetooth: btusb: Don't fail external suspend requests · 61071229
      Luiz Augusto von Dentz authored
      Commit 4e0a1d8b
      ("Bluetooth: btusb: Don't suspend when there are connections")
      introduces a check for connections to prevent auto-suspend but that
      actually ignored the fact the .suspend callback can be called for
      external suspend requests which
      Documentation/driver-api/usb/power-management.rst states the following:
      
       'External suspend calls should never be allowed to fail in this way,
       only autosuspend calls.  The driver can tell them apart by applying
       the :c:func:`PMSG_IS_AUTO` macro to the message argument to the
       ``suspend`` method; it will return True for internal PM events
       (autosuspend) and False for external PM events.'
      
      In addition to that align system suspend with USB suspend by using
      hci_suspend_dev since otherwise the stack would be expecting events
      such as advertising reports which may not be delivered while the
      transport is suspended.
      
      Fixes: 4e0a1d8b ("Bluetooth: btusb: Don't suspend when there are connections")
      Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
      Tested-by: default avatarKiran K <kiran.k@intel.com>
      61071229
    • Luiz Augusto von Dentz's avatar
      Bluetooth: hci_conn: Fix UAF in hci_enhanced_setup_sync · 18fd04ad
      Luiz Augusto von Dentz authored
      This checks if the ACL connection remains valid as it could be destroyed
      while hci_enhanced_setup_sync is pending on cmd_sync leading to the
      following trace:
      
      BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0x91b/0xa60
      Read of size 1 at addr ffff888002328ffd by task kworker/u5:2/37
      
      CPU: 0 UID: 0 PID: 37 Comm: kworker/u5:2 Not tainted 6.11.0-rc6-01300-g810be445d8d6 #7099
      Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014
      Workqueue: hci0 hci_cmd_sync_work
      Call Trace:
       <TASK>
       dump_stack_lvl+0x5d/0x80
       ? hci_enhanced_setup_sync+0x91b/0xa60
       print_report+0x152/0x4c0
       ? hci_enhanced_setup_sync+0x91b/0xa60
       ? __virt_addr_valid+0x1fa/0x420
       ? hci_enhanced_setup_sync+0x91b/0xa60
       kasan_report+0xda/0x1b0
       ? hci_enhanced_setup_sync+0x91b/0xa60
       hci_enhanced_setup_sync+0x91b/0xa60
       ? __pfx_hci_enhanced_setup_sync+0x10/0x10
       ? __pfx___mutex_lock+0x10/0x10
       hci_cmd_sync_work+0x1c2/0x330
       process_one_work+0x7d9/0x1360
       ? __pfx_lock_acquire+0x10/0x10
       ? __pfx_process_one_work+0x10/0x10
       ? assign_work+0x167/0x240
       worker_thread+0x5b7/0xf60
       ? __kthread_parkme+0xac/0x1c0
       ? __pfx_worker_thread+0x10/0x10
       ? __pfx_worker_thread+0x10/0x10
       kthread+0x293/0x360
       ? __pfx_kthread+0x10/0x10
       ret_from_fork+0x2f/0x70
       ? __pfx_kthread+0x10/0x10
       ret_from_fork_asm+0x1a/0x30
       </TASK>
      
      Allocated by task 34:
       kasan_save_stack+0x30/0x50
       kasan_save_track+0x14/0x30
       __kasan_kmalloc+0x8f/0xa0
       __hci_conn_add+0x187/0x17d0
       hci_connect_sco+0x2e1/0xb90
       sco_sock_connect+0x2a2/0xb80
       __sys_connect+0x227/0x2a0
       __x64_sys_connect+0x6d/0xb0
       do_syscall_64+0x71/0x140
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
      
      Freed by task 37:
       kasan_save_stack+0x30/0x50
       kasan_save_track+0x14/0x30
       kasan_save_free_info+0x3b/0x60
       __kasan_slab_free+0x101/0x160
       kfree+0xd0/0x250
       device_release+0x9a/0x210
       kobject_put+0x151/0x280
       hci_conn_del+0x448/0xbf0
       hci_abort_conn_sync+0x46f/0x980
       hci_cmd_sync_work+0x1c2/0x330
       process_one_work+0x7d9/0x1360
       worker_thread+0x5b7/0xf60
       kthread+0x293/0x360
       ret_from_fork+0x2f/0x70
       ret_from_fork_asm+0x1a/0x30
      
      Cc: stable@vger.kernel.org
      Fixes: e07a06b4 ("Bluetooth: Convert SCO configure_datapath to hci_sync")
      Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
      18fd04ad
    • Luiz Augusto von Dentz's avatar
      Bluetooth: RFCOMM: FIX possible deadlock in rfcomm_sk_state_change · 08d19142
      Luiz Augusto von Dentz authored
      rfcomm_sk_state_change attempts to use sock_lock so it must never be
      called with it locked but rfcomm_sock_ioctl always attempt to lock it
      causing the following trace:
      
      ======================================================
      WARNING: possible circular locking dependency detected
      6.8.0-syzkaller-08951-gfe46a7dd #0 Not tainted
      ------------------------------------------------------
      syz-executor386/5093 is trying to acquire lock:
      ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1671 [inline]
      ffff88807c396258 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}, at: rfcomm_sk_state_change+0x5b/0x310 net/bluetooth/rfcomm/sock.c:73
      
      but task is already holding lock:
      ffff88807badfd28 (&d->lock){+.+.}-{3:3}, at: __rfcomm_dlc_close+0x226/0x6a0 net/bluetooth/rfcomm/core.c:491
      
      Reported-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com
      Tested-by: syzbot+d7ce59b06b3eb14fd218@syzkaller.appspotmail.com
      Closes: https://syzkaller.appspot.com/bug?extid=d7ce59b06b3eb14fd218
      Fixes: 3241ad82 ("[Bluetooth] Add timestamp support to L2CAP, RFCOMM and SCO")
      Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
      08d19142
    • Kory Maincent's avatar
      net: pse-pd: Fix enabled status mismatch · dda3529d
      Kory Maincent authored
      PSE controllers like the TPS23881 can forcefully turn off their
      configuration state. In such cases, the is_enabled() and get_status()
      callbacks will report the PSE as disabled, while admin_state_enabled
      will show it as enabled. This mismatch can lead the user to attempt
      to enable it, but no action is taken as admin_state_enabled remains set.
      
      The solution is to disable the PSE before enabling it, ensuring the
      actual status matches admin_state_enabled.
      
      Fixes: d83e1376 ("net: pse-pd: Use regulator framework within PSE framework")
      Signed-off-by: default avatarKory Maincent <kory.maincent@bootlin.com>
      Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
      Link: https://patch.msgid.link/20241002121706.246143-1-kory.maincent@bootlin.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      dda3529d
    • Kacper Ludwinski's avatar
      selftests: net: no_forwarding: fix VID for $swp2 in one_bridge_two_pvids() test · 9f49d14e
      Kacper Ludwinski authored
      Currently, the second bridge command overwrites the first one.
      Fix this by adding this VID to the interface behind $swp2.
      
      The one_bridge_two_pvids() test intends to check that there is no
      leakage of traffic between bridge ports which have a single VLAN - the
      PVID VLAN.
      
      Because of a typo, port $swp1 is configured with a PVID twice (second
      command overwrites first), and $swp2 isn't configured at all (and since
      the bridge vlan_default_pvid property is set to 0, this port will not
      have a PVID at all, so it will drop all untagged and priority-tagged
      traffic).
      
      So, instead of testing the configuration that was intended, we are
      testing a different one, where one port has PVID 2 and the other has
      no PVID. This incorrect version of the test should also pass, but is
      ineffective for its purpose, so fix the typo.
      
      This typo has an impact on results of the test,
      potentially leading to wrong conclusions regarding
      the functionality of a network device.
      
      The tests results:
      
      TEST: Switch ports in VLAN-aware bridge with different PVIDs:
      	Unicast non-IP untagged   [ OK ]
      	Multicast non-IP untagged   [ OK ]
      	Broadcast non-IP untagged   [ OK ]
      	Unicast IPv4 untagged   [ OK ]
      	Multicast IPv4 untagged   [ OK ]
      	Unicast IPv6 untagged   [ OK ]
      	Multicast IPv6 untagged   [ OK ]
      	Unicast non-IP VID 1   [ OK ]
      	Multicast non-IP VID 1   [ OK ]
      	Broadcast non-IP VID 1   [ OK ]
      	Unicast IPv4 VID 1   [ OK ]
      	Multicast IPv4 VID 1   [ OK ]
      	Unicast IPv6 VID 1   [ OK ]
      	Multicast IPv6 VID 1   [ OK ]
      	Unicast non-IP VID 4094   [ OK ]
      	Multicast non-IP VID 4094   [ OK ]
      	Broadcast non-IP VID 4094   [ OK ]
      	Unicast IPv4 VID 4094   [ OK ]
      	Multicast IPv4 VID 4094   [ OK ]
      	Unicast IPv6 VID 4094   [ OK ]
      	Multicast IPv6 VID 4094   [ OK ]
      
      Fixes: 476a4f05 ("selftests: forwarding: add a no_forwarding.sh test")
      Reviewed-by: default avatarHangbin Liu <liuhangbin@gmail.com>
      Reviewed-by: default avatarShuah Khan <skhan@linuxfoundation.org>
      Signed-off-by: default avatarKacper Ludwinski <kac.ludwinski@icloud.com>
      Link: https://patch.msgid.link/20241002051016.849-1-kac.ludwinski@icloud.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      9f49d14e
    • Jakub Kicinski's avatar
      Merge branch 'ibmvnic-fix-for-send-scrq-direct' · 500257db
      Jakub Kicinski authored
      Nick Child says:
      
      ====================
      ibmvnic: Fix for send scrq direct
      
      This is a v2 of a patchset (now just patch) which addresses a
      bug in a new feature which is causing major link UP issues with
      certain physical cards.
      
      For a full summary of the issue:
        1. During vnic initialization we get the following values from vnic
           server regarding "Transmit / Receive Descriptor Requirement" (see
            PAPR Table 584. CAPABILITIES Commands):
          - LSO Tx frame = 0x0F , header offsets + L2, L3, L4 headers required
          - CSO Tx frame = 0x0C , header offsets + L2 header required
          - standard frame = 0x0C , header offsets + L2 header required
        2. Assume we are dealing with only "standard frames" from now on (no
           CSO, no LSO)
        3. When using 100G backing device, we don't hand vnic server any header
           information and TX is successful
        4. When using 25G backing device, we don't hand vnic server any header
          information and TX fails and we get "Adapter Error" transport events.
      The obvious issue here is that vnic client should be respecting the 0X0C
      header requirement for standard frames.  But 100G cards will also give
      0x0C despite the fact that we know TX works if we ignore it. That being
      said, we still must respect values given from the managing server. Will
      need to work with them going forward to hopefully get 100G cards to
      return 0x00 for this bitstring so the performance gains of using
      send_subcrq_direct can be continued.
      ====================
      
      Link: https://patch.msgid.link/20241001163200.1802522-1-nnac123@linux.ibm.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      500257db
    • Nick Child's avatar
      ibmvnic: Inspect header requirements before using scrq direct · de390657
      Nick Child authored
      Previously, the TX header requirement for standard frames was ignored.
      This requirement is a bitstring sent from the VIOS which maps to the
      type of header information needed during TX. If no header information,
      is needed then send subcrq direct can be used (which can be more
      performant).
      
      This bitstring was previously ignored for standard packets (AKA non LSO,
      non CSO) due to the belief that the bitstring was over-cautionary. It
      turns out that there are some configurations where the backing device
      does need header information for transmission of standard packets. If
      the information is not supplied then this causes continuous "Adapter
      error" transport events. Therefore, this bitstring should be respected
      and observed before considering the use of send subcrq direct.
      
      Fixes: 74839f7a ("ibmvnic: Introduce send sub-crq direct")
      Signed-off-by: default avatarNick Child <nnac123@linux.ibm.com>
      Reviewed-by: default avatarSimon Horman <horms@kernel.org>
      Link: https://patch.msgid.link/20241001163200.1802522-2-nnac123@linux.ibm.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      de390657
    • Jakub Kicinski's avatar
      Merge branch 'netfilter-br_netfilter-fix-panic-with-metadata_dst-skb' · 69ea1d4a
      Jakub Kicinski authored
      Andy Roulin says:
      
      ====================
      netfilter: br_netfilter: fix panic with metadata_dst skb
      
      There's a kernel panic possible in the br_netfilter module when sending
      untagged traffic via a VxLAN device. Traceback is included below.
      This happens during the check for fragmentation in br_nf_dev_queue_xmit
      if the MTU on the VxLAN device is not big enough.
      
      It is dependent on:
      1) the br_netfilter module being loaded;
      2) net.bridge.bridge-nf-call-iptables set to 1;
      3) a bridge with a VxLAN (single-vxlan-device) netdevice as a bridge port;
      4) untagged frames with size higher than the VxLAN MTU forwarded/flooded
      
      This case was never supported in the first place, so the first patch drops
      such packets.
      
      A regression selftest is added as part of the second patch.
      
      PING 10.0.0.2 (10.0.0.2) from 0.0.0.0 h1-eth0: 2000(2028) bytes of data.
      [  176.291791] Unable to handle kernel NULL pointer dereference at
      virtual address 0000000000000110
      [  176.292101] Mem abort info:
      [  176.292184]   ESR = 0x0000000096000004
      [  176.292322]   EC = 0x25: DABT (current EL), IL = 32 bits
      [  176.292530]   SET = 0, FnV = 0
      [  176.292709]   EA = 0, S1PTW = 0
      [  176.292862]   FSC = 0x04: level 0 translation fault
      [  176.293013] Data abort info:
      [  176.293104]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
      [  176.293488]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
      [  176.293787]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
      [  176.293995] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000043ef5000
      [  176.294166] [0000000000000110] pgd=0000000000000000,
      p4d=0000000000000000
      [  176.294827] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
      [  176.295252] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel veth
      br_netfilter bridge stp llc ipv6 crct10dif_ce
      [  176.295923] CPU: 0 PID: 188 Comm: ping Not tainted
      6.8.0-rc3-g5b3fbd61 #2
      [  176.296314] Hardware name: linux,dummy-virt (DT)
      [  176.296535] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS
      BTYPE=--)
      [  176.296808] pc : br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]
      [  176.297382] lr : br_nf_dev_queue_xmit+0x2ac/0x4ec [br_netfilter]
      [  176.297636] sp : ffff800080003630
      [  176.297743] x29: ffff800080003630 x28: 0000000000000008 x27:
      ffff6828c49ad9f8
      [  176.298093] x26: ffff6828c49ad000 x25: 0000000000000000 x24:
      00000000000003e8
      [  176.298430] x23: 0000000000000000 x22: ffff6828c4960b40 x21:
      ffff6828c3b16d28
      [  176.298652] x20: ffff6828c3167048 x19: ffff6828c3b16d00 x18:
      0000000000000014
      [  176.298926] x17: ffffb0476322f000 x16: ffffb7e164023730 x15:
      0000000095744632
      [  176.299296] x14: ffff6828c3f1c880 x13: 0000000000000002 x12:
      ffffb7e137926a70
      [  176.299574] x11: 0000000000000001 x10: ffff6828c3f1c898 x9 :
      0000000000000000
      [  176.300049] x8 : ffff6828c49bf070 x7 : 0008460f18d5f20e x6 :
      f20e0100bebafeca
      [  176.300302] x5 : ffff6828c7f918fe x4 : ffff6828c49bf070 x3 :
      0000000000000000
      [  176.300586] x2 : 0000000000000000 x1 : ffff6828c3c7ad00 x0 :
      ffff6828c7f918f0
      [  176.300889] Call trace:
      [  176.301123]  br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]
      [  176.301411]  br_nf_post_routing+0x2a8/0x3e4 [br_netfilter]
      [  176.301703]  nf_hook_slow+0x48/0x124
      [  176.302060]  br_forward_finish+0xc8/0xe8 [bridge]
      [  176.302371]  br_nf_hook_thresh+0x124/0x134 [br_netfilter]
      [  176.302605]  br_nf_forward_finish+0x118/0x22c [br_netfilter]
      [  176.302824]  br_nf_forward_ip.part.0+0x264/0x290 [br_netfilter]
      [  176.303136]  br_nf_forward+0x2b8/0x4e0 [br_netfilter]
      [  176.303359]  nf_hook_slow+0x48/0x124
      [  176.303803]  __br_forward+0xc4/0x194 [bridge]
      [  176.304013]  br_flood+0xd4/0x168 [bridge]
      [  176.304300]  br_handle_frame_finish+0x1d4/0x5c4 [bridge]
      [  176.304536]  br_nf_hook_thresh+0x124/0x134 [br_netfilter]
      [  176.304978]  br_nf_pre_routing_finish+0x29c/0x494 [br_netfilter]
      [  176.305188]  br_nf_pre_routing+0x250/0x524 [br_netfilter]
      [  176.305428]  br_handle_frame+0x244/0x3cc [bridge]
      [  176.305695]  __netif_receive_skb_core.constprop.0+0x33c/0xecc
      [  176.306080]  __netif_receive_skb_one_core+0x40/0x8c
      [  176.306197]  __netif_receive_skb+0x18/0x64
      [  176.306369]  process_backlog+0x80/0x124
      [  176.306540]  __napi_poll+0x38/0x17c
      [  176.306636]  net_rx_action+0x124/0x26c
      [  176.306758]  __do_softirq+0x100/0x26c
      [  176.307051]  ____do_softirq+0x10/0x1c
      [  176.307162]  call_on_irq_stack+0x24/0x4c
      [  176.307289]  do_softirq_own_stack+0x1c/0x2c
      [  176.307396]  do_softirq+0x54/0x6c
      [  176.307485]  __local_bh_enable_ip+0x8c/0x98
      [  176.307637]  __dev_queue_xmit+0x22c/0xd28
      [  176.307775]  neigh_resolve_output+0xf4/0x1a0
      [  176.308018]  ip_finish_output2+0x1c8/0x628
      [  176.308137]  ip_do_fragment+0x5b4/0x658
      [  176.308279]  ip_fragment.constprop.0+0x48/0xec
      [  176.308420]  __ip_finish_output+0xa4/0x254
      [  176.308593]  ip_finish_output+0x34/0x130
      [  176.308814]  ip_output+0x6c/0x108
      [  176.308929]  ip_send_skb+0x50/0xf0
      [  176.309095]  ip_push_pending_frames+0x30/0x54
      [  176.309254]  raw_sendmsg+0x758/0xaec
      [  176.309568]  inet_sendmsg+0x44/0x70
      [  176.309667]  __sys_sendto+0x110/0x178
      [  176.309758]  __arm64_sys_sendto+0x28/0x38
      [  176.309918]  invoke_syscall+0x48/0x110
      [  176.310211]  el0_svc_common.constprop.0+0x40/0xe0
      [  176.310353]  do_el0_svc+0x1c/0x28
      [  176.310434]  el0_svc+0x34/0xb4
      [  176.310551]  el0t_64_sync_handler+0x120/0x12c
      [  176.310690]  el0t_64_sync+0x190/0x194
      [  176.311066] Code: f9402e61 79402aa2 927ff821 f9400023 (f9408860)
      [  176.315743] ---[ end trace 0000000000000000 ]---
      [  176.316060] Kernel panic - not syncing: Oops: Fatal exception in
      interrupt
      [  176.316371] Kernel Offset: 0x37e0e3000000 from 0xffff800080000000
      [  176.316564] PHYS_OFFSET: 0xffff97d780000000
      [  176.316782] CPU features: 0x0,88000203,3c020000,0100421b
      [  176.317210] Memory Limit: none
      [  176.317527] ---[ end Kernel panic - not syncing: Oops: Fatal
      Exception in interrupt ]---\
      ====================
      
      Link: https://patch.msgid.link/20241001154400.22787-1-aroulin@nvidia.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      69ea1d4a
    • Andy Roulin's avatar
      selftests: add regression test for br_netfilter panic · bc4d22b7
      Andy Roulin authored
      Add a new netfilter selftests to test against br_netfilter panics when
      VxLAN single-device is used together with untagged traffic and high MTU.
      Reviewed-by: default avatarPetr Machata <petrm@nvidia.com>
      Signed-off-by: default avatarAndy Roulin <aroulin@nvidia.com>
      Acked-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
      Link: https://patch.msgid.link/20241001154400.22787-3-aroulin@nvidia.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      bc4d22b7
    • Andy Roulin's avatar
      netfilter: br_netfilter: fix panic with metadata_dst skb · f9ff7665
      Andy Roulin authored
      Fix a kernel panic in the br_netfilter module when sending untagged
      traffic via a VxLAN device.
      This happens during the check for fragmentation in br_nf_dev_queue_xmit.
      
      It is dependent on:
      1) the br_netfilter module being loaded;
      2) net.bridge.bridge-nf-call-iptables set to 1;
      3) a bridge with a VxLAN (single-vxlan-device) netdevice as a bridge port;
      4) untagged frames with size higher than the VxLAN MTU forwarded/flooded
      
      When forwarding the untagged packet to the VxLAN bridge port, before
      the netfilter hooks are called, br_handle_egress_vlan_tunnel is called and
      changes the skb_dst to the tunnel dst. The tunnel_dst is a metadata type
      of dst, i.e., skb_valid_dst(skb) is false, and metadata->dst.dev is NULL.
      
      Then in the br_netfilter hooks, in br_nf_dev_queue_xmit, there's a check
      for frames that needs to be fragmented: frames with higher MTU than the
      VxLAN device end up calling br_nf_ip_fragment, which in turns call
      ip_skb_dst_mtu.
      
      The ip_dst_mtu tries to use the skb_dst(skb) as if it was a valid dst
      with valid dst->dev, thus the crash.
      
      This case was never supported in the first place, so drop the packet
      instead.
      
      PING 10.0.0.2 (10.0.0.2) from 0.0.0.0 h1-eth0: 2000(2028) bytes of data.
      [  176.291791] Unable to handle kernel NULL pointer dereference at
      virtual address 0000000000000110
      [  176.292101] Mem abort info:
      [  176.292184]   ESR = 0x0000000096000004
      [  176.292322]   EC = 0x25: DABT (current EL), IL = 32 bits
      [  176.292530]   SET = 0, FnV = 0
      [  176.292709]   EA = 0, S1PTW = 0
      [  176.292862]   FSC = 0x04: level 0 translation fault
      [  176.293013] Data abort info:
      [  176.293104]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
      [  176.293488]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
      [  176.293787]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
      [  176.293995] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000043ef5000
      [  176.294166] [0000000000000110] pgd=0000000000000000,
      p4d=0000000000000000
      [  176.294827] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
      [  176.295252] Modules linked in: vxlan ip6_udp_tunnel udp_tunnel veth
      br_netfilter bridge stp llc ipv6 crct10dif_ce
      [  176.295923] CPU: 0 PID: 188 Comm: ping Not tainted
      6.8.0-rc3-g5b3fbd61 #2
      [  176.296314] Hardware name: linux,dummy-virt (DT)
      [  176.296535] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS
      BTYPE=--)
      [  176.296808] pc : br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]
      [  176.297382] lr : br_nf_dev_queue_xmit+0x2ac/0x4ec [br_netfilter]
      [  176.297636] sp : ffff800080003630
      [  176.297743] x29: ffff800080003630 x28: 0000000000000008 x27:
      ffff6828c49ad9f8
      [  176.298093] x26: ffff6828c49ad000 x25: 0000000000000000 x24:
      00000000000003e8
      [  176.298430] x23: 0000000000000000 x22: ffff6828c4960b40 x21:
      ffff6828c3b16d28
      [  176.298652] x20: ffff6828c3167048 x19: ffff6828c3b16d00 x18:
      0000000000000014
      [  176.298926] x17: ffffb0476322f000 x16: ffffb7e164023730 x15:
      0000000095744632
      [  176.299296] x14: ffff6828c3f1c880 x13: 0000000000000002 x12:
      ffffb7e137926a70
      [  176.299574] x11: 0000000000000001 x10: ffff6828c3f1c898 x9 :
      0000000000000000
      [  176.300049] x8 : ffff6828c49bf070 x7 : 0008460f18d5f20e x6 :
      f20e0100bebafeca
      [  176.300302] x5 : ffff6828c7f918fe x4 : ffff6828c49bf070 x3 :
      0000000000000000
      [  176.300586] x2 : 0000000000000000 x1 : ffff6828c3c7ad00 x0 :
      ffff6828c7f918f0
      [  176.300889] Call trace:
      [  176.301123]  br_nf_dev_queue_xmit+0x390/0x4ec [br_netfilter]
      [  176.301411]  br_nf_post_routing+0x2a8/0x3e4 [br_netfilter]
      [  176.301703]  nf_hook_slow+0x48/0x124
      [  176.302060]  br_forward_finish+0xc8/0xe8 [bridge]
      [  176.302371]  br_nf_hook_thresh+0x124/0x134 [br_netfilter]
      [  176.302605]  br_nf_forward_finish+0x118/0x22c [br_netfilter]
      [  176.302824]  br_nf_forward_ip.part.0+0x264/0x290 [br_netfilter]
      [  176.303136]  br_nf_forward+0x2b8/0x4e0 [br_netfilter]
      [  176.303359]  nf_hook_slow+0x48/0x124
      [  176.303803]  __br_forward+0xc4/0x194 [bridge]
      [  176.304013]  br_flood+0xd4/0x168 [bridge]
      [  176.304300]  br_handle_frame_finish+0x1d4/0x5c4 [bridge]
      [  176.304536]  br_nf_hook_thresh+0x124/0x134 [br_netfilter]
      [  176.304978]  br_nf_pre_routing_finish+0x29c/0x494 [br_netfilter]
      [  176.305188]  br_nf_pre_routing+0x250/0x524 [br_netfilter]
      [  176.305428]  br_handle_frame+0x244/0x3cc [bridge]
      [  176.305695]  __netif_receive_skb_core.constprop.0+0x33c/0xecc
      [  176.306080]  __netif_receive_skb_one_core+0x40/0x8c
      [  176.306197]  __netif_receive_skb+0x18/0x64
      [  176.306369]  process_backlog+0x80/0x124
      [  176.306540]  __napi_poll+0x38/0x17c
      [  176.306636]  net_rx_action+0x124/0x26c
      [  176.306758]  __do_softirq+0x100/0x26c
      [  176.307051]  ____do_softirq+0x10/0x1c
      [  176.307162]  call_on_irq_stack+0x24/0x4c
      [  176.307289]  do_softirq_own_stack+0x1c/0x2c
      [  176.307396]  do_softirq+0x54/0x6c
      [  176.307485]  __local_bh_enable_ip+0x8c/0x98
      [  176.307637]  __dev_queue_xmit+0x22c/0xd28
      [  176.307775]  neigh_resolve_output+0xf4/0x1a0
      [  176.308018]  ip_finish_output2+0x1c8/0x628
      [  176.308137]  ip_do_fragment+0x5b4/0x658
      [  176.308279]  ip_fragment.constprop.0+0x48/0xec
      [  176.308420]  __ip_finish_output+0xa4/0x254
      [  176.308593]  ip_finish_output+0x34/0x130
      [  176.308814]  ip_output+0x6c/0x108
      [  176.308929]  ip_send_skb+0x50/0xf0
      [  176.309095]  ip_push_pending_frames+0x30/0x54
      [  176.309254]  raw_sendmsg+0x758/0xaec
      [  176.309568]  inet_sendmsg+0x44/0x70
      [  176.309667]  __sys_sendto+0x110/0x178
      [  176.309758]  __arm64_sys_sendto+0x28/0x38
      [  176.309918]  invoke_syscall+0x48/0x110
      [  176.310211]  el0_svc_common.constprop.0+0x40/0xe0
      [  176.310353]  do_el0_svc+0x1c/0x28
      [  176.310434]  el0_svc+0x34/0xb4
      [  176.310551]  el0t_64_sync_handler+0x120/0x12c
      [  176.310690]  el0t_64_sync+0x190/0x194
      [  176.311066] Code: f9402e61 79402aa2 927ff821 f9400023 (f9408860)
      [  176.315743] ---[ end trace 0000000000000000 ]---
      [  176.316060] Kernel panic - not syncing: Oops: Fatal exception in
      interrupt
      [  176.316371] Kernel Offset: 0x37e0e3000000 from 0xffff800080000000
      [  176.316564] PHYS_OFFSET: 0xffff97d780000000
      [  176.316782] CPU features: 0x0,88000203,3c020000,0100421b
      [  176.317210] Memory Limit: none
      [  176.317527] ---[ end Kernel panic - not syncing: Oops: Fatal
      Exception in interrupt ]---\
      
      Fixes: 11538d03 ("bridge: vlan dst_metadata hooks in ingress and egress paths")
      Reviewed-by: default avatarIdo Schimmel <idosch@nvidia.com>
      Signed-off-by: default avatarAndy Roulin <aroulin@nvidia.com>
      Acked-by: default avatarNikolay Aleksandrov <razor@blackwall.org>
      Link: https://patch.msgid.link/20241001154400.22787-2-aroulin@nvidia.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      f9ff7665
    • Vladimir Oltean's avatar
      net: dsa: sja1105: fix reception from VLAN-unaware bridges · 1f9fc48f
      Vladimir Oltean authored
      The blamed commit introduced an unexpected regression in the sja1105
      driver. Packets from VLAN-unaware bridge ports get received correctly,
      but the protocol stack can't seem to decode them properly.
      
      For ds->untag_bridge_pvid users (thus also sja1105), the blamed commit
      did introduce a functional change: dsa_switch_rcv() used to call
      dsa_untag_bridge_pvid(), which looked like this:
      
      	err = br_vlan_get_proto(br, &proto);
      	if (err)
      		return skb;
      
      	/* Move VLAN tag from data to hwaccel */
      	if (!skb_vlan_tag_present(skb) && skb->protocol == htons(proto)) {
      		skb = skb_vlan_untag(skb);
      		if (!skb)
      			return NULL;
      	}
      
      and now it calls dsa_software_vlan_untag() which has just this:
      
      	/* Move VLAN tag from data to hwaccel */
      	if (!skb_vlan_tag_present(skb)) {
      		skb = skb_vlan_untag(skb);
      		if (!skb)
      			return NULL;
      	}
      
      thus lacks any skb->protocol == bridge VLAN protocol check. That check
      is deferred until a later check for skb->vlan_proto (in the hwaccel area).
      
      The new code is problematic because, for VLAN-untagged packets,
      skb_vlan_untag() blindly takes the 4 bytes starting with the EtherType
      and turns them into a hwaccel VLAN tag. This is what breaks the protocol
      stack.
      
      It would be tempting to "make it work as before" and only call
      skb_vlan_untag() for those packets with the skb->protocol actually
      representing a VLAN.
      
      But the premise of the newly introduced dsa_software_vlan_untag() core
      function is not wrong. Drivers set ds->untag_bridge_pvid or
      ds->untag_vlan_aware_bridge_pvid presumably because they send all
      traffic to the CPU reception path as VLAN-tagged. So why should we spend
      any additional CPU cycles assuming that the packet may be VLAN-untagged?
      And why does the sja1105 driver opt into ds->untag_bridge_pvid if it
      doesn't always deliver packets to the CPU as VLAN-tagged?
      
      The answer to the latter question is indeed more interesting: it doesn't
      need to. This got done in commit 884be12f ("net: dsa: sja1105: add
      support for imprecise RX"), because I thought it would be needed, but I
      didn't realize that it doesn't actually make a difference.
      
      As explained in the commit message of the blamed patch, ds->untag_bridge_pvid
      only makes a difference in the VLAN-untagged receive path of a bridge port.
      However, in that operating mode, tag_sja1105.c makes use of VLAN tags
      with the ETH_P_SJA1105 TPID, and it decodes and consumes these VLAN tags
      as if they were DSA tags (aka tag_8021q operation). Even if commit
      884be12f ("net: dsa: sja1105: add support for imprecise RX") added
      this logic in sja1105_bridge_vlan_add():
      
      	/* Always install bridge VLANs as egress-tagged on the CPU port. */
      	if (dsa_is_cpu_port(ds, port))
      		flags = 0;
      
      that was for _bridge_ VLANs, which are _not_ committed to hardware
      in VLAN-unaware mode (aka the mode where ds->untag_bridge_pvid does
      anything at all). Even prior to that change, the tag_8021q VLANs
      were always installed as egress-tagged on the CPU port, see
      dsa_switch_tag_8021q_vlan_add():
      
      	u16 flags = 0; // egress-tagged, non-PVID
      
      	if (dsa_port_is_user(dp))
      		flags |= BRIDGE_VLAN_INFO_UNTAGGED |
      			 BRIDGE_VLAN_INFO_PVID;
      
      	err = dsa_port_do_tag_8021q_vlan_add(dp, info->vid,
      					     flags);
      	if (err)
      		return err;
      
      Whether the sja1105 driver needs the new flag, ds->untag_vlan_aware_bridge_pvid,
      rather than ds->untag_bridge_pvid, is a separate discussion. To fix the
      current bug in VLAN-unaware bridge mode, I would argue that the sja1105
      driver should not request something it doesn't need, rather than
      complicating the core DSA helper. Whereas before the blamed commit, this
      setting was harmless, now it has caused breakage.
      
      Fixes: 93e4649e ("net: dsa: provide a software untagging function on RX for VLAN-aware bridges")
      Signed-off-by: default avatarVladimir Oltean <vladimir.oltean@nxp.com>
      Link: https://patch.msgid.link/20241001140206.50933-1-vladimir.oltean@nxp.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      1f9fc48f
    • Jakub Kicinski's avatar
      Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue · 096c0fa4
      Jakub Kicinski authored
      Tony Nguyen says:
      
      ====================
      Intel Wired LAN Driver Updates 2024-09-30 (ice, idpf)
      
      This series contains updates to ice and idpf drivers:
      
      For ice:
      
      Michal corrects setting of dst VSI on LAN filters and adds clearing of
      port VLAN configuration during reset.
      
      Gui-Dong Han corrects failures to decrement refcount in some error
      paths.
      
      Przemek resolves a memory leak in ice_init_tx_topology().
      
      Arkadiusz prevents setting of DPLL_PIN_STATE_SELECTABLE to an improper
      value.
      
      Dave stops clearing of VLAN tracking bit to allow for VLANs to be properly
      restored after reset.
      
      For idpf:
      
      Ahmed sets uninitialized dyn_ctl_intrvl_s value.
      
      Josh corrects use and reporting of mailbox size.
      
      Larysa corrects order of function calls during de-initialization.
      
      * '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue:
        idpf: deinit virtchnl transaction manager after vport and vectors
        idpf: use actual mbx receive payload length
        idpf: fix VF dynamic interrupt ctl register initialization
        ice: fix VLAN replay after reset
        ice: disallow DPLL_PIN_STATE_SELECTABLE for dpll output pins
        ice: fix memleak in ice_init_tx_topology()
        ice: clear port vlan config during reset
        ice: Fix improper handling of refcount in ice_sriov_set_msix_vec_count()
        ice: Fix improper handling of refcount in ice_dpll_init_rclk_pins()
        ice: set correct dst VSI in only LAN filters
      ====================
      
      Link: https://patch.msgid.link/20240930223601.3137464-1-anthony.l.nguyen@intel.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      096c0fa4
  4. 03 Oct, 2024 8 commits
    • Leo Stone's avatar
      Documentation: networking/tcp_ao: typo and grammar fixes · 2d7a098b
      Leo Stone authored
      Fix multiple grammatical issues and add a missing period to improve
      readability.
      Signed-off-by: default avatarLeo Stone <leocstone@gmail.com>
      Reviewed-by: default avatarSimon Horman <horms@kernel.org>
      Link: https://patch.msgid.link/20240929005001.370991-1-leocstone@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      2d7a098b
    • Jakub Kicinski's avatar
      Merge branch 'rxrpc-miscellaneous-fixes' · 35f12108
      Jakub Kicinski authored
      David Howells says:
      
      ====================
      rxrpc: Miscellaneous fixes
      
      Here some miscellaneous fixes for AF_RXRPC:
      
       (1) Fix a race in the I/O thread vs UDP socket setup.
      
       (2) Fix an uninitialised variable.
      ====================
      
      Link: https://patch.msgid.link/20241001132702.3122709-1-dhowells@redhat.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      35f12108
    • David Howells's avatar
      rxrpc: Fix uninitialised variable in rxrpc_send_data() · 7a310f8d
      David Howells authored
      Fix the uninitialised txb variable in rxrpc_send_data() by moving the code
      that loads it above all the jumps to maybe_error, txb being stored back
      into call->tx_pending right before the normal return.
      
      Fixes: b0f571ec ("rxrpc: Fix locking in rxrpc's sendmsg")
      Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
      Closes: https://lists.infradead.org/pipermail/linux-afs/2024-October/008896.htmlSigned-off-by: default avatarDavid Howells <dhowells@redhat.com>
      cc: Marc Dionne <marc.dionne@auristor.com>
      cc: linux-afs@lists.infradead.org
      Link: https://patch.msgid.link/20241001132702.3122709-3-dhowells@redhat.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      7a310f8d
    • David Howells's avatar
      rxrpc: Fix a race between socket set up and I/O thread creation · bc212465
      David Howells authored
      In rxrpc_open_socket(), it sets up the socket and then sets up the I/O
      thread that will handle it.  This is a problem, however, as there's a gap
      between the two phases in which a packet may come into rxrpc_encap_rcv()
      from the UDP packet but we oops when trying to wake the not-yet created I/O
      thread.
      
      As a quick fix, just make rxrpc_encap_rcv() discard the packet if there's
      no I/O thread yet.
      
      A better, but more intrusive fix would perhaps be to rearrange things such
      that the socket creation is done by the I/O thread.
      
      Fixes: a275da62 ("rxrpc: Create a per-local endpoint receive queue and I/O thread")
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      cc: yuxuanzhe@outlook.com
      cc: Marc Dionne <marc.dionne@auristor.com>
      cc: Simon Horman <horms@kernel.org>
      cc: linux-afs@lists.infradead.org
      Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
      Link: https://patch.msgid.link/20241001132702.3122709-2-dhowells@redhat.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      bc212465
    • Jakub Kicinski's avatar
      Merge branch 'tcp-3-fixes-for-retrans_stamp-and-undo-logic' · 9af25dd9
      Jakub Kicinski authored
      Neal Cardwell says:
      
      ====================
      tcp: 3 fixes for retrans_stamp and undo logic
      
      Geumhwan Yu <geumhwan.yu@samsung.com> recently reported and diagnosed
      a regression in TCP loss recovery undo logic in the case where a TCP
      connection enters fast recovery, is unable to retransmit anything due to
      TSQ, and then receives an ACK allowing forward progress. The sender should
      be able to undo the spurious loss recovery in this case, but was not doing
      so. The first patch fixes this regression.
      
      Running our suite of packetdrill tests with the first fix, the tests
      highlighted two other small bugs in the way retrans_stamp is updated in
      some rare corner cases. The second two patches fix those other two small
      bugs.
      
      Thanks to Geumhwan Yu for the bug report!
      ====================
      
      Link: https://patch.msgid.link/20241001200517.2756803-1-ncardwell.sw@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      9af25dd9
    • Neal Cardwell's avatar
      tcp: fix TFO SYN_RECV to not zero retrans_stamp with retransmits out · 27c80efc
      Neal Cardwell authored
      Fix tcp_rcv_synrecv_state_fastopen() to not zero retrans_stamp
      if retransmits are outstanding.
      
      tcp_fastopen_synack_timer() sets retrans_stamp, so typically we'll
      need to zero retrans_stamp here to prevent spurious
      retransmits_timed_out(). The logic to zero retrans_stamp is from this
      2019 commit:
      
      commit cd736d8b ("tcp: fix retrans timestamp on passive Fast Open")
      
      However, in the corner case where the ACK of our TFO SYNACK carried
      some SACK blocks that caused us to enter TCP_CA_Recovery then that
      non-zero retrans_stamp corresponds to the active fast recovery, and we
      need to leave retrans_stamp with its current non-zero value, for
      correct ETIMEDOUT and undo behavior.
      
      Fixes: cd736d8b ("tcp: fix retrans timestamp on passive Fast Open")
      Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
      Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Link: https://patch.msgid.link/20241001200517.2756803-4-ncardwell.sw@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      27c80efc
    • Neal Cardwell's avatar
      tcp: fix tcp_enter_recovery() to zero retrans_stamp when it's safe · b41b4cbd
      Neal Cardwell authored
      Fix tcp_enter_recovery() so that if there are no retransmits out then
      we zero retrans_stamp when entering fast recovery. This is necessary
      to fix two buggy behaviors.
      
      Currently a non-zero retrans_stamp value can persist across multiple
      back-to-back loss recovery episodes. This is because we generally only
      clears retrans_stamp if we are completely done with loss recoveries,
      and get to tcp_try_to_open() and find !tcp_any_retrans_done(sk). This
      behavior causes two bugs:
      
      (1) When a loss recovery episode (CA_Loss or CA_Recovery) is followed
      immediately by a new CA_Recovery, the retrans_stamp value can persist
      and can be a time before this new CA_Recovery episode starts. That
      means that timestamp-based undo will be using the wrong retrans_stamp
      (a value that is too old) when comparing incoming TS ecr values to
      retrans_stamp to see if the current fast recovery episode can be
      undone.
      
      (2) If there is a roughly minutes-long sequence of back-to-back fast
      recovery episodes, one after another (e.g. in a shallow-buffered or
      policed bottleneck), where each fast recovery successfully makes
      forward progress and recovers one window of sequence space (but leaves
      at least one retransmit in flight at the end of the recovery),
      followed by several RTOs, then the ETIMEDOUT check may be using the
      wrong retrans_stamp (a value set at the start of the first fast
      recovery in the sequence). This can cause a very premature ETIMEDOUT,
      killing the connection prematurely.
      
      This commit changes the code to zero retrans_stamp when entering fast
      recovery, when this is known to be safe (no retransmits are out in the
      network). That ensures that when starting a fast recovery episode, and
      it is safe to do so, retrans_stamp is set when we send the fast
      retransmit packet. That addresses both bug (1) and bug (2) by ensuring
      that (if no retransmits are out when we start a fast recovery) we use
      the initial fast retransmit of this fast recovery as the time value
      for undo and ETIMEDOUT calculations.
      
      This makes intuitive sense, since the start of a new fast recovery
      episode (in a scenario where no lost packets are out in the network)
      means that the connection has made forward progress since the last RTO
      or fast recovery, and we should thus "restart the clock" used for both
      undo and ETIMEDOUT logic.
      
      Note that if when we start fast recovery there *are* retransmits out
      in the network, there can still be undesirable (1)/(2) issues. For
      example, after this patch we can still have the (1) and (2) problems
      in cases like this:
      
      + round 1: sender sends flight 1
      
      + round 2: sender receives SACKs and enters fast recovery 1,
        retransmits some packets in flight 1 and then sends some new data as
        flight 2
      
      + round 3: sender receives some SACKs for flight 2, notes losses, and
        retransmits some packets to fill the holes in flight 2
      
      + fast recovery has some lost retransmits in flight 1 and continues
        for one or more rounds sending retransmits for flight 1 and flight 2
      
      + fast recovery 1 completes when snd_una reaches high_seq at end of
        flight 1
      
      + there are still holes in the SACK scoreboard in flight 2, so we
        enter fast recovery 2, but some retransmits in the flight 2 sequence
        range are still in flight (retrans_out > 0), so we can't execute the
        new retrans_stamp=0 added here to clear retrans_stamp
      
      It's not yet clear how to fix these remaining (1)/(2) issues in an
      efficient way without breaking undo behavior, given that retrans_stamp
      is currently used for undo and ETIMEDOUT. Perhaps the optimal (but
      expensive) strategy would be to set retrans_stamp to the timestamp of
      the earliest outstanding retransmit when entering fast recovery. But
      at least this commit makes things better.
      
      Note that this does not change the semantics of retrans_stamp; it
      simply makes retrans_stamp accurate in some cases where it was not
      before:
      
      (1) Some loss recovery, followed by an immediate entry into a fast
      recovery, where there are no retransmits out when entering the fast
      recovery.
      
      (2) When a TFO server has a SYNACK retransmit that sets retrans_stamp,
      and then the ACK that completes the 3-way handshake has SACK blocks
      that trigger a fast recovery. In this case when entering fast recovery
      we want to zero out the retrans_stamp from the TFO SYNACK retransmit,
      and set the retrans_stamp based on the timestamp of the fast recovery.
      
      We introduce a tcp_retrans_stamp_cleanup() helper, because this
      two-line sequence already appears in 3 places and is about to appear
      in 2 more as a result of this bug fix patch series. Once this bug fix
      patches series in the net branch makes it into the net-next branch
      we'll update the 3 other call sites to use the new helper.
      
      This is a long-standing issue. The Fixes tag below is chosen to be the
      oldest commit at which the patch will apply cleanly, which is from
      Linux v3.5 in 2012.
      
      Fixes: 1fbc3405 ("tcp: early retransmit: tcp_enter_recovery()")
      Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
      Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Link: https://patch.msgid.link/20241001200517.2756803-3-ncardwell.sw@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      b41b4cbd
    • Neal Cardwell's avatar
      tcp: fix to allow timestamp undo if no retransmits were sent · e37ab737
      Neal Cardwell authored
      Fix the TCP loss recovery undo logic in tcp_packet_delayed() so that
      it can trigger undo even if TSQ prevents a fast recovery episode from
      reaching tcp_retransmit_skb().
      
      Geumhwan Yu <geumhwan.yu@samsung.com> recently reported that after
      this commit from 2019:
      
      commit bc9f38c8 ("tcp: avoid unconditional congestion window undo
      on SYN retransmit")
      
      ...and before this fix we could have buggy scenarios like the
      following:
      
      + Due to reordering, a TCP connection receives some SACKs and enters a
        spurious fast recovery.
      
      + TSQ prevents all invocations of tcp_retransmit_skb(), because many
        skbs are queued in lower layers of the sending machine's network
        stack; thus tp->retrans_stamp remains 0.
      
      + The connection receives a TCP timestamp ECR value echoing a
        timestamp before the fast recovery, indicating that the fast
        recovery was spurious.
      
      + The connection fails to undo the spurious fast recovery because
        tp->retrans_stamp is 0, and thus tcp_packet_delayed() returns false,
        due to the new logic in the 2019 commit: commit bc9f38c8 ("tcp:
        avoid unconditional congestion window undo on SYN retransmit")
      
      This fix tweaks the logic to be more similar to the
      tcp_packet_delayed() logic before bc9f38c8, except that we take
      care not to be fooled by the FLAG_SYN_ACKED code path zeroing out
      tp->retrans_stamp (the bug noted and fixed by Yuchung in
      bc9f38c8).
      
      Note that this returns the high-level behavior of tcp_packet_delayed()
      to again match the comment for the function, which says: "Nothing was
      retransmitted or returned timestamp is less than timestamp of the
      first retransmission." Note that this comment is in the original
      2005-04-16 Linux git commit, so this is evidently long-standing
      behavior.
      
      Fixes: bc9f38c8 ("tcp: avoid unconditional congestion window undo on SYN retransmit")
      Reported-by: default avatarGeumhwan Yu <geumhwan.yu@samsung.com>
      Diagnosed-by: default avatarGeumhwan Yu <geumhwan.yu@samsung.com>
      Signed-off-by: default avatarNeal Cardwell <ncardwell@google.com>
      Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Link: https://patch.msgid.link/20241001200517.2756803-2-ncardwell.sw@gmail.comSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
      e37ab737