1. 21 Oct, 2017 9 commits
    • David S. Miller's avatar
      Merge tag 'linux-can-fixes-for-4.14-20171019' of... · c69d75ae
      David S. Miller authored
      Merge tag 'linux-can-fixes-for-4.14-20171019' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can
      
      Marc Kleine-Budde says:
      
      ====================
      pull-request: can 2017-10-19
      
      this is a pull request of 11 patches for the upcoming 4.14 release.
      
      There are 6 patches by ZHU Yi for the flexcan driver, that work around
      the CAN error handling state transition problems found in various
      incarnations of the flexcan IP core.
      
      The patch by Colin Ian King fixes a potential NULL pointer deref in the
      CAN broad cast manager (bcm). One patch by me replaces a direct deref of a RCU
      protected pointer by rcu_access_pointer. My second patch adds missing
      OOM error handling in af_can. A patch by Stefan Mätje for the esd_usb2
      driver fixes the dlc in received RTR frames. And the last patch is by
      Wolfgang Grandegger, it fixes a busy loop in the gs_usb driver in case
      it runs out of TX contexts.
      ====================
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c69d75ae
    • Dexuan Cui's avatar
      hv_sock: add locking in the open/close/release code paths · b4562ca7
      Dexuan Cui authored
      Without the patch, when hvs_open_connection() hasn't completely established
      a connection (e.g. it has changed sk->sk_state to SS_CONNECTED, but hasn't
      inserted the sock into the connected queue), vsock_stream_connect() may see
      the sk_state change and return the connection to the userspace, and next
      when the userspace closes the connection quickly, hvs_release() may not see
      the connection in the connected queue; finally hvs_open_connection()
      inserts the connection into the queue, but we won't be able to purge the
      connection for ever.
      Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
      Cc: K. Y. Srinivasan <kys@microsoft.com>
      Cc: Haiyang Zhang <haiyangz@microsoft.com>
      Cc: Stephen Hemminger <sthemmin@microsoft.com>
      Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
      Cc: Cathy Avery <cavery@redhat.com>
      Cc: Rolf Neugebauer <rolf.neugebauer@docker.com>
      Cc: Marcelo Cerri <marcelo.cerri@canonical.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      b4562ca7
    • Gavin Shan's avatar
      net/ncsi: Fix length of GVI response packet · 0a90e251
      Gavin Shan authored
      The length of GVI (GetVersionInfo) response packet should be 40 instead
      of 36. This issue was found from /sys/kernel/debug/ncsi/eth0/stats.
      
       # ethtool --ncsi eth0 swstats
           :
       RESPONSE     OK       TIMEOUT  ERROR
       =======================================
       GVI          0        0        2
      
      With this applied, no error reported on GVI response packets:
      
       # ethtool --ncsi eth0 swstats
           :
       RESPONSE     OK       TIMEOUT  ERROR
       =======================================
       GVI          2        0        0
      Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
      Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0a90e251
    • Gavin Shan's avatar
      net/ncsi: Enforce failover on link monitor timeout · 52b4c862
      Gavin Shan authored
      The NCSI channel has been configured to provide service if its link
      monitor timer is enabled, regardless of its state (inactive or active).
      So the timeout event on the link monitor indicates the out-of-service
      on that channel, for which a failover is needed.
      
      This sets NCSI_DEV_RESHUFFLE flag to enforce failover on link monitor
      timeout, regardless the channel's original state (inactive or active).
      Also, the link is put into "down" state to give the failing channel
      lowest priority when selecting for the active channel. The state of
      failing channel should be set to active in order for deinitialization
      and failover to be done.
      Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
      Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      52b4c862
    • Gavin Shan's avatar
      net/ncsi: Disable HWA mode when no channels are found · 100ef01f
      Gavin Shan authored
      When there are no NCSI channels probed, HWA (Hardware Arbitration)
      mode is enabled. It's not correct because HWA depends on the fact:
      NCSI channels exist and all of them support HWA mode. This disables
      HWA when no channels are probed.
      Signed-off-by: default avatarGavin Shan <gwshan@linux.vnet.ibm.com>
      Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      100ef01f
    • Samuel Mendoza-Jonas's avatar
      net/ncsi: Stop monitor if channel times out or is inactive · 0795fb20
      Samuel Mendoza-Jonas authored
      ncsi_channel_monitor() misses stopping the channel monitor in several
      places that it should, causing a WARN_ON_ONCE() to trigger when the
      monitor is re-started later, eg:
      
      [  459.040000] WARNING: CPU: 0 PID: 1093 at net/ncsi/ncsi-manage.c:269 ncsi_start_channel_monitor+0x7c/0x90
      [  459.040000] CPU: 0 PID: 1093 Comm: kworker/0:3 Not tainted 4.10.17-gaca2fdd #140
      [  459.040000] Hardware name: ASpeed SoC
      [  459.040000] Workqueue: events ncsi_dev_work
      [  459.040000] [<80010094>] (unwind_backtrace) from [<8000d950>] (show_stack+0x20/0x24)
      [  459.040000] [<8000d950>] (show_stack) from [<801dbf70>] (dump_stack+0x20/0x28)
      [  459.040000] [<801dbf70>] (dump_stack) from [<80018d7c>] (__warn+0xe0/0x108)
      [  459.040000] [<80018d7c>] (__warn) from [<80018e70>] (warn_slowpath_null+0x30/0x38)
      [  459.040000] [<80018e70>] (warn_slowpath_null) from [<803f6a08>] (ncsi_start_channel_monitor+0x7c/0x90)
      [  459.040000] [<803f6a08>] (ncsi_start_channel_monitor) from [<803f7664>] (ncsi_configure_channel+0xdc/0x5fc)
      [  459.040000] [<803f7664>] (ncsi_configure_channel) from [<803f8160>] (ncsi_dev_work+0xac/0x474)
      [  459.040000] [<803f8160>] (ncsi_dev_work) from [<8002d244>] (process_one_work+0x1e0/0x450)
      [  459.040000] [<8002d244>] (process_one_work) from [<8002d510>] (worker_thread+0x5c/0x570)
      [  459.040000] [<8002d510>] (worker_thread) from [<80033614>] (kthread+0x124/0x164)
      [  459.040000] [<80033614>] (kthread) from [<8000a5e8>] (ret_from_fork+0x14/0x2c)
      
      This also updates the monitor instead of just returning if
      ncsi_xmit_cmd() fails to send the get-link-status command so that the
      monitor properly times out.
      
      Fixes: e6f44ed6 "net/ncsi: Package and channel management"
      Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0795fb20
    • Samuel Mendoza-Jonas's avatar
      net/ncsi: Fix AEN HNCDSC packet length · 6850d0f8
      Samuel Mendoza-Jonas authored
      Correct the value of the HNCDSC AEN packet.
      Fixes: 7a82ecf4 "net/ncsi: NCSI AEN packet handler"
      Signed-off-by: default avatarSamuel Mendoza-Jonas <sam@mendozajonas.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      6850d0f8
    • Eric Dumazet's avatar
      packet: avoid panic in packet_getsockopt() · 509c7a1e
      Eric Dumazet authored
      syzkaller got crashes in packet_getsockopt() processing
      PACKET_ROLLOVER_STATS command while another thread was managing
      to change po->rollover
      
      Using RCU will fix this bug. We might later add proper RCU annotations
      for sparse sake.
      
      In v2: I replaced kfree(rollover) in fanout_add() to kfree_rcu()
      variant, as spotted by John.
      
      Fixes: a9b63918 ("packet: rollover statistics")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Cc: Willem de Bruijn <willemb@google.com>
      Cc: John Sperbeck <jsperbeck@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      509c7a1e
    • Eric Dumazet's avatar
      tcp/dccp: fix ireq->opt races · c92e8c02
      Eric Dumazet authored
      syzkaller found another bug in DCCP/TCP stacks [1]
      
      For the reasons explained in commit ce105008 ("tcp/dccp: fix
      ireq->pktopts race"), we need to make sure we do not access
      ireq->opt unless we own the request sock.
      
      Note the opt field is renamed to ireq_opt to ease grep games.
      
      [1]
      BUG: KASAN: use-after-free in ip_queue_xmit+0x1687/0x18e0 net/ipv4/ip_output.c:474
      Read of size 1 at addr ffff8801c951039c by task syz-executor5/3295
      
      CPU: 1 PID: 3295 Comm: syz-executor5 Not tainted 4.14.0-rc4+ #80
      Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
      Call Trace:
       __dump_stack lib/dump_stack.c:16 [inline]
       dump_stack+0x194/0x257 lib/dump_stack.c:52
       print_address_description+0x73/0x250 mm/kasan/report.c:252
       kasan_report_error mm/kasan/report.c:351 [inline]
       kasan_report+0x25b/0x340 mm/kasan/report.c:409
       __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:427
       ip_queue_xmit+0x1687/0x18e0 net/ipv4/ip_output.c:474
       tcp_transmit_skb+0x1ab7/0x3840 net/ipv4/tcp_output.c:1135
       tcp_send_ack.part.37+0x3bb/0x650 net/ipv4/tcp_output.c:3587
       tcp_send_ack+0x49/0x60 net/ipv4/tcp_output.c:3557
       __tcp_ack_snd_check+0x2c6/0x4b0 net/ipv4/tcp_input.c:5072
       tcp_ack_snd_check net/ipv4/tcp_input.c:5085 [inline]
       tcp_rcv_state_process+0x2eff/0x4850 net/ipv4/tcp_input.c:6071
       tcp_child_process+0x342/0x990 net/ipv4/tcp_minisocks.c:816
       tcp_v4_rcv+0x1827/0x2f80 net/ipv4/tcp_ipv4.c:1682
       ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_local_deliver+0x1ce/0x6e0 net/ipv4/ip_input.c:257
       dst_input include/net/dst.h:464 [inline]
       ip_rcv_finish+0x887/0x19a0 net/ipv4/ip_input.c:397
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_rcv+0xc3f/0x1820 net/ipv4/ip_input.c:493
       __netif_receive_skb_core+0x1a3e/0x34b0 net/core/dev.c:4476
       __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4514
       netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4587
       netif_receive_skb+0xae/0x390 net/core/dev.c:4611
       tun_rx_batched.isra.50+0x5ed/0x860 drivers/net/tun.c:1372
       tun_get_user+0x249c/0x36d0 drivers/net/tun.c:1766
       tun_chr_write_iter+0xbf/0x160 drivers/net/tun.c:1792
       call_write_iter include/linux/fs.h:1770 [inline]
       new_sync_write fs/read_write.c:468 [inline]
       __vfs_write+0x68a/0x970 fs/read_write.c:481
       vfs_write+0x18f/0x510 fs/read_write.c:543
       SYSC_write fs/read_write.c:588 [inline]
       SyS_write+0xef/0x220 fs/read_write.c:580
       entry_SYSCALL_64_fastpath+0x1f/0xbe
      RIP: 0033:0x40c341
      RSP: 002b:00007f469523ec10 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
      RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 000000000040c341
      RDX: 0000000000000037 RSI: 0000000020004000 RDI: 0000000000000015
      RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
      R10: 00000000000f4240 R11: 0000000000000293 R12: 00000000004b7fd1
      R13: 00000000ffffffff R14: 0000000020000000 R15: 0000000000025000
      
      Allocated by task 3295:
       save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
       __do_kmalloc mm/slab.c:3725 [inline]
       __kmalloc+0x162/0x760 mm/slab.c:3734
       kmalloc include/linux/slab.h:498 [inline]
       tcp_v4_save_options include/net/tcp.h:1962 [inline]
       tcp_v4_init_req+0x2d3/0x3e0 net/ipv4/tcp_ipv4.c:1271
       tcp_conn_request+0xf6d/0x3410 net/ipv4/tcp_input.c:6283
       tcp_v4_conn_request+0x157/0x210 net/ipv4/tcp_ipv4.c:1313
       tcp_rcv_state_process+0x8ea/0x4850 net/ipv4/tcp_input.c:5857
       tcp_v4_do_rcv+0x55c/0x7d0 net/ipv4/tcp_ipv4.c:1482
       tcp_v4_rcv+0x2d10/0x2f80 net/ipv4/tcp_ipv4.c:1711
       ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_local_deliver+0x1ce/0x6e0 net/ipv4/ip_input.c:257
       dst_input include/net/dst.h:464 [inline]
       ip_rcv_finish+0x887/0x19a0 net/ipv4/ip_input.c:397
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_rcv+0xc3f/0x1820 net/ipv4/ip_input.c:493
       __netif_receive_skb_core+0x1a3e/0x34b0 net/core/dev.c:4476
       __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4514
       netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4587
       netif_receive_skb+0xae/0x390 net/core/dev.c:4611
       tun_rx_batched.isra.50+0x5ed/0x860 drivers/net/tun.c:1372
       tun_get_user+0x249c/0x36d0 drivers/net/tun.c:1766
       tun_chr_write_iter+0xbf/0x160 drivers/net/tun.c:1792
       call_write_iter include/linux/fs.h:1770 [inline]
       new_sync_write fs/read_write.c:468 [inline]
       __vfs_write+0x68a/0x970 fs/read_write.c:481
       vfs_write+0x18f/0x510 fs/read_write.c:543
       SYSC_write fs/read_write.c:588 [inline]
       SyS_write+0xef/0x220 fs/read_write.c:580
       entry_SYSCALL_64_fastpath+0x1f/0xbe
      
      Freed by task 3306:
       save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
       save_stack+0x43/0xd0 mm/kasan/kasan.c:447
       set_track mm/kasan/kasan.c:459 [inline]
       kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
       __cache_free mm/slab.c:3503 [inline]
       kfree+0xca/0x250 mm/slab.c:3820
       inet_sock_destruct+0x59d/0x950 net/ipv4/af_inet.c:157
       __sk_destruct+0xfd/0x910 net/core/sock.c:1560
       sk_destruct+0x47/0x80 net/core/sock.c:1595
       __sk_free+0x57/0x230 net/core/sock.c:1603
       sk_free+0x2a/0x40 net/core/sock.c:1614
       sock_put include/net/sock.h:1652 [inline]
       inet_csk_complete_hashdance+0xd5/0xf0 net/ipv4/inet_connection_sock.c:959
       tcp_check_req+0xf4d/0x1620 net/ipv4/tcp_minisocks.c:765
       tcp_v4_rcv+0x17f6/0x2f80 net/ipv4/tcp_ipv4.c:1675
       ip_local_deliver_finish+0x2e2/0xba0 net/ipv4/ip_input.c:216
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_local_deliver+0x1ce/0x6e0 net/ipv4/ip_input.c:257
       dst_input include/net/dst.h:464 [inline]
       ip_rcv_finish+0x887/0x19a0 net/ipv4/ip_input.c:397
       NF_HOOK include/linux/netfilter.h:249 [inline]
       ip_rcv+0xc3f/0x1820 net/ipv4/ip_input.c:493
       __netif_receive_skb_core+0x1a3e/0x34b0 net/core/dev.c:4476
       __netif_receive_skb+0x2c/0x1b0 net/core/dev.c:4514
       netif_receive_skb_internal+0x10b/0x670 net/core/dev.c:4587
       netif_receive_skb+0xae/0x390 net/core/dev.c:4611
       tun_rx_batched.isra.50+0x5ed/0x860 drivers/net/tun.c:1372
       tun_get_user+0x249c/0x36d0 drivers/net/tun.c:1766
       tun_chr_write_iter+0xbf/0x160 drivers/net/tun.c:1792
       call_write_iter include/linux/fs.h:1770 [inline]
       new_sync_write fs/read_write.c:468 [inline]
       __vfs_write+0x68a/0x970 fs/read_write.c:481
       vfs_write+0x18f/0x510 fs/read_write.c:543
       SYSC_write fs/read_write.c:588 [inline]
       SyS_write+0xef/0x220 fs/read_write.c:580
       entry_SYSCALL_64_fastpath+0x1f/0xbe
      
      Fixes: e994b2f0 ("tcp: do not lock listener to process SYN packets")
      Fixes: 079096f1 ("tcp/dccp: install syn_recv requests into ehash table")
      Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c92e8c02
  2. 20 Oct, 2017 7 commits
  3. 19 Oct, 2017 20 commits
  4. 18 Oct, 2017 4 commits
    • Jakub Kicinski's avatar
      bpf: disallow arithmetic operations on context pointer · 28e33f9d
      Jakub Kicinski authored
      Commit f1174f77 ("bpf/verifier: rework value tracking")
      removed the crafty selection of which pointer types are
      allowed to be modified.  This is OK for most pointer types
      since adjust_ptr_min_max_vals() will catch operations on
      immutable pointers.  One exception is PTR_TO_CTX which is
      now allowed to be offseted freely.
      
      The intent of aforementioned commit was to allow context
      access via modified registers.  The offset passed to
      ->is_valid_access() verifier callback has been adjusted
      by the value of the variable offset.
      
      What is missing, however, is taking the variable offset
      into account when the context register is used.  Or in terms
      of the code adding the offset to the value passed to the
      ->convert_ctx_access() callback.  This leads to the following
      eBPF user code:
      
           r1 += 68
           r0 = *(u32 *)(r1 + 8)
           exit
      
      being translated to this in kernel space:
      
         0: (07) r1 += 68
         1: (61) r0 = *(u32 *)(r1 +180)
         2: (95) exit
      
      Offset 8 is corresponding to 180 in the kernel, but offset
      76 is valid too.  Verifier will "accept" access to offset
      68+8=76 but then "convert" access to offset 8 as 180.
      Effective access to offset 248 is beyond the kernel context.
      (This is a __sk_buff example on a debug-heavy kernel -
      packet mark is 8 -> 180, 76 would be data.)
      
      Dereferencing the modified context pointer is not as easy
      as dereferencing other types, because we have to translate
      the access to reading a field in kernel structures which is
      usually at a different offset and often of a different size.
      To allow modifying the pointer we would have to make sure
      that given eBPF instruction will always access the same
      field or the fields accessed are "compatible" in terms of
      offset and size...
      
      Disallow dereferencing modified context pointers and add
      to selftests the test case described here.
      
      Fixes: f1174f77 ("bpf/verifier: rework value tracking")
      Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
      Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
      Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Acked-by: default avatarEdward Cree <ecree@solarflare.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      28e33f9d
    • Johannes Berg's avatar
      netlink: fix netlink_ack() extack race · 48044eb4
      Johannes Berg authored
      It seems that it's possible to toggle NETLINK_F_EXT_ACK
      through setsockopt() while another thread/CPU is building
      a message inside netlink_ack(), which could then trigger
      the WARN_ON()s I added since if it goes from being turned
      off to being turned on between allocating and filling the
      message, the skb could end up being too small.
      
      Avoid this whole situation by storing the value of this
      flag in a separate variable and using that throughout the
      function instead.
      
      Fixes: 2d4bc933 ("netlink: extended ACK reporting")
      Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      48044eb4
    • Thomas Falcon's avatar
      ibmvnic: Fix calculation of number of TX header descriptors · 2de09681
      Thomas Falcon authored
      This patch correctly sets the number of additional header descriptors
      that will be sent in an indirect SCRQ entry.
      Signed-off-by: default avatarThomas Falcon <tlfalcon@linux.vnet.ibm.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2de09681
    • Ido Schimmel's avatar
      mlxsw: core: Fix possible deadlock · d965465b
      Ido Schimmel authored
      When an EMAD is transmitted, a timeout work item is scheduled with a
      delay of 200ms, so that another EMAD will be retried until a maximum of
      five retries.
      
      In certain situations, it's possible for the function waiting on the
      EMAD to be associated with a work item that is queued on the same
      workqueue (`mlxsw_core`) as the timeout work item. This results in
      flushing a work item on the same workqueue.
      
      According to commit e159489b ("workqueue: relax lockdep annotation
      on flush_work()") the above may lead to a deadlock in case the workqueue
      has only one worker active or if the system in under memory pressure and
      the rescue worker is in use. The latter explains the very rare and
      random nature of the lockdep splats we have been seeing:
      
      [   52.730240] ============================================
      [   52.736179] WARNING: possible recursive locking detected
      [   52.742119] 4.14.0-rc3jiri+ #4 Not tainted
      [   52.746697] --------------------------------------------
      [   52.752635] kworker/1:3/599 is trying to acquire lock:
      [   52.758378]  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c4fa4>] flush_work+0x3a4/0x5e0
      [   52.767837]
                     but task is already holding lock:
      [   52.774360]  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
      [   52.784495]
                     other info that might help us debug this:
      [   52.791794]  Possible unsafe locking scenario:
      [   52.798413]        CPU0
      [   52.801144]        ----
      [   52.803875]   lock(mlxsw_core_driver_name);
      [   52.808556]   lock(mlxsw_core_driver_name);
      [   52.813236]
                      *** DEADLOCK ***
      [   52.819857]  May be due to missing lock nesting notation
      [   52.827450] 3 locks held by kworker/1:3/599:
      [   52.832221]  #0:  (mlxsw_core_driver_name){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
      [   52.842846]  #1:  ((&(&bridge->fdb_notify.dw)->work)){+.+.}, at: [<ffffffff811c65c4>] process_one_work+0x7d4/0x12f0
      [   52.854537]  #2:  (rtnl_mutex){+.+.}, at: [<ffffffff822ad8e7>] rtnl_lock+0x17/0x20
      [   52.863021]
                     stack backtrace:
      [   52.867890] CPU: 1 PID: 599 Comm: kworker/1:3 Not tainted 4.14.0-rc3jiri+ #4
      [   52.875773] Hardware name: Mellanox Technologies Ltd. "MSN2100-CB2F"/"SA001017", BIOS 5.6.5 06/07/2016
      [   52.886267] Workqueue: mlxsw_core mlxsw_sp_fdb_notify_work [mlxsw_spectrum]
      [   52.894060] Call Trace:
      [   52.909122]  __lock_acquire+0xf6f/0x2a10
      [   53.025412]  lock_acquire+0x158/0x440
      [   53.047557]  flush_work+0x3c4/0x5e0
      [   53.087571]  __cancel_work_timer+0x3ca/0x5e0
      [   53.177051]  cancel_delayed_work_sync+0x13/0x20
      [   53.182142]  mlxsw_reg_trans_bulk_wait+0x12d/0x7a0 [mlxsw_core]
      [   53.194571]  mlxsw_core_reg_access+0x586/0x990 [mlxsw_core]
      [   53.225365]  mlxsw_reg_query+0x10/0x20 [mlxsw_core]
      [   53.230882]  mlxsw_sp_fdb_notify_work+0x2a3/0x9d0 [mlxsw_spectrum]
      [   53.237801]  process_one_work+0x8f1/0x12f0
      [   53.321804]  worker_thread+0x1fd/0x10c0
      [   53.435158]  kthread+0x28e/0x370
      [   53.448703]  ret_from_fork+0x2a/0x40
      [   53.453017] mlxsw_spectrum 0000:01:00.0: EMAD retries (2/5) (tid=bf4549b100000774)
      [   53.453119] mlxsw_spectrum 0000:01:00.0: EMAD retries (5/5) (tid=bf4549b100000770)
      [   53.453132] mlxsw_spectrum 0000:01:00.0: EMAD reg access failed (tid=bf4549b100000770,reg_id=200b(sfn),type=query,status=0(operation performed))
      [   53.453143] mlxsw_spectrum 0000:01:00.0: Failed to get FDB notifications
      
      Fix this by creating another workqueue for EMAD timeouts, thereby
      preventing the situation of a work item trying to flush a work item
      queued on the same workqueue.
      
      Fixes: caf7297e ("mlxsw: core: Introduce support for asynchronous EMAD register access")
      Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
      Reported-by: default avatarJiri Pirko <jiri@mellanox.com>
      Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d965465b