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  1. 02 Oct, 2020 5 commits
    • Saeed Mahameed's avatar
      net/mlx5: cmdif, Avoid skipping reclaim pages if FW is not accessible · b898ce7b
      Saeed Mahameed authored 
      In case of pci is offline reclaim_pages_cmd() will still try to call
the FW to release FW pages, cmd_exec() in this case will return a silent
success without actually calling the FW.

This is wrong and will cause page leaks, what we should do is to detect
pci offline or command interface un-available before tying to access the
FW and manually release the FW pages in the driver.

In this patch we share the code to check for FW command interface
availability and we call it in sensitive places e.g. reclaim_pages_cmd().

Alternative fix:
 1. Remove MLX5_CMD_OP_MANAGE_PAGES form mlx5_internal_err_ret_value,
    command success simulation list.
 2. Always Release FW pages even if cmd_exec fails in reclaim_pages_cmd().
Reviewed-by: default avatarMoshe Shemesh <moshe@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
      b898ce7b
    • Eran Ben Elisha's avatar
      net/mlx5: Add retry mechanism to the command entry index allocation · 410bd754
      Eran Ben Elisha authored 
      It is possible that new command entry index allocation will temporarily
fail. The new command holds the semaphore, so it means that a free entry
should be ready soon. Add one second retry mechanism before returning an
error.

Patch "net/mlx5: Avoid possible free of command entry while timeout comp
handler" increase the possibility to bump into this temporarily failure
as it delays the entry index release for non-callback commands.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: default avatarEran Ben Elisha <eranbe@nvidia.com>
Reviewed-by: default avatarMoshe Shemesh <moshe@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
      410bd754
    • Eran Ben Elisha's avatar
      net/mlx5: poll cmd EQ in case of command timeout · 1d5558b1
      Eran Ben Elisha authored 
      Once driver detects a command interface command timeout, it warns the
user and returns timeout error to the caller. In such case, the entry of
the command is not evacuated (because only real event interrupt is allowed
to clear command interface entry). If the HW event interrupt
of this entry will never arrive, this entry will be left unused forever.
Command interface entries are limited and eventually we can end up without
the ability to post a new command.

In addition, if driver will not consume the EQE of the lost interrupt and
rearm the EQ, no new interrupts will arrive for other commands.

Add a resiliency mechanism for manually polling the command EQ in case of
a command timeout. In case resiliency mechanism will find non-handled EQE,
it will consume it, and the command interface will be fully functional
again. Once the resiliency flow finished, wait another 5 seconds for the
command interface to complete for this command entry.

Define mlx5_cmd_eq_recover() to manage the cmd EQ polling resiliency flow.
Add an async EQ spinlock to avoid races between resiliency flows and real
interrupts that might run simultaneously.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: default avatarEran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
      1d5558b1
    • Eran Ben Elisha's avatar
      net/mlx5: Avoid possible free of command entry while timeout comp handler · 50b2412b
      Eran Ben Elisha authored 
      Upon command completion timeout, driver simulates a forced command
completion. In a rare case where real interrupt for that command arrives
simultaneously, it might release the command entry while the forced
handler might still access it.

Fix that by adding an entry refcount, to track current amount of allowed
handlers. Command entry to be released only when this refcount is
decremented to zero.

Command refcount is always initialized to one. For callback commands,
command completion handler is the symmetric flow to decrement it. For
non-callback commands, it is wait_func().

Before ringing the doorbell, increment the refcount for the real completion
handler. Once the real completion handler is called, it will decrement it.

For callback commands, once the delayed work is scheduled, increment the
refcount. Upon callback command completion handler, we will try to cancel
the timeout callback. In case of success, we need to decrement the callback
refcount as it will never run.

In addition, gather the entry index free and the entry free into a one
flow for all command types release.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: default avatarEran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: default avatarMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
      50b2412b
    • Eran Ben Elisha's avatar
      net/mlx5: Fix a race when moving command interface to polling mode · 432161ea
      Eran Ben Elisha authored 
      As part of driver unload, it destroys the commands EQ (via FW command).
As the commands EQ is destroyed, FW will not generate EQEs for any command
that driver sends afterwards. Driver should poll for later commands status.

Driver commands mode metadata is updated before the commands EQ is
actually destroyed. This can lead for double completion handle by the
driver (polling and interrupt), if a command is executed and completed by
FW after the mode was changed, but before the EQ was destroyed.

Fix that by using the mlx5_cmd_allowed_opcode mechanism to guarantee
that only DESTROY_EQ command can be executed during this time period.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: default avatarEran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: default avatarMoshe Shemesh <moshe@mellanox.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
      432161ea
  3. 30 Sep, 2020 12 commits
  5. 29 Sep, 2020 16 commits
  7. 28 Sep, 2020 7 commits
    • Manivannan Sadhasivam's avatar
      net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks · a7809ff9
      Manivannan Sadhasivam authored 
      The rcu read locks are needed to avoid potential race condition while
dereferencing radix tree from multiple threads. The issue was identified
by syzbot. Below is the crash report:

=============================
WARNING: suspicious RCU usage
5.7.0-syzkaller #0 Not tainted
-----------------------------
include/linux/radix-tree.h:176 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u4:1/21:
 #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline]
 #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2241
 #1: ffffc90000dd7d80 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2243

stack backtrace:
CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: qrtr_ns_handler qrtr_ns_worker
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1e9/0x30e lib/dump_stack.c:118
 radix_tree_deref_slot include/linux/radix-tree.h:176 [inline]
 ctrl_cmd_new_lookup net/qrtr/ns.c:558 [inline]
 qrtr_ns_worker+0x2aff/0x4500 net/qrtr/ns.c:674
 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268
 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414
 kthread+0x353/0x380 kernel/kthread.c:268

Fixes: 0c2204a4 ("net: qrtr: Migrate nameservice to kernel from userspace")
Reported-and-tested-by: syzbot+0f84f6eed90503da72fc@syzkaller.appspotmail.com
Signed-off-by: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      a7809ff9
    • David S. Miller's avatar
      Merge branch 'net-core-fix-a-lockdep-splat-in-the-dev_addr_list' · 0ba56b89
      David S. Miller authored 
      Taehee Yoo says:

====================
net: core: fix a lockdep splat in the dev_addr_list.

This patchset is to avoid lockdep splat.

When a stacked interface graph is changed, netif_addr_lock() is called
recursively and it internally calls spin_lock_nested().
The parameter of spin_lock_nested() is 'dev->lower_level',
this is called subclass.
The problem of 'dev->lower_level' is that while 'dev->lower_level' is
being used as a subclass of spin_lock_nested(), its value can be changed.
So, spin_lock_nested() would be called recursively with the same
subclass value, the lockdep understands a deadlock.
In order to avoid this, a new variable is needed and it is going to be
used as a parameter of spin_lock_nested().
The first and second patch is a preparation patch for the third patch.
In the third patch, the problem will be fixed.

The first patch is to add __netdev_upper_dev_unlink().
An existed netdev_upper_dev_unlink() is renamed to
__netdev_upper_dev_unlink(). and netdev_upper_dev_unlink()
is added as an wrapper of this function.

The second patch is to add the netdev_nested_priv structure.
netdev_walk_all_{ upper | lower }_dev() pass both private functions
and "data" pointer to handle their own things.
At this point, the data pointer type is void *.
In order to make it easier to expand common variables and functions,
this new netdev_nested_priv structure is added.

The third patch is to add a new variable 'nested_level'
into the net_device structure.
This variable will be used as a parameter of spin_lock_nested() of
dev->addr_list_lock.
Due to this variable, it can avoid lockdep splat.
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      0ba56b89
    • Taehee Yoo's avatar
      net: core: add nested_level variable in net_device · 1fc70edb
      Taehee Yoo authored 
      This patch is to add a new variable 'nested_level' into the net_device
structure.
This variable will be used as a parameter of spin_lock_nested() of
dev->addr_list_lock.

netif_addr_lock() can be called recursively so spin_lock_nested() is
used instead of spin_lock() and dev->lower_level is used as a parameter
of spin_lock_nested().
But, dev->lower_level value can be updated while it is being used.
So, lockdep would warn a possible deadlock scenario.

When a stacked interface is deleted, netif_{uc | mc}_sync() is
called recursively.
So, spin_lock_nested() is called recursively too.
At this moment, the dev->lower_level variable is used as a parameter of it.
dev->lower_level value is updated when interfaces are being unlinked/linked
immediately.
Thus, After unlinking, dev->lower_level shouldn't be a parameter of
spin_lock_nested().

    A (macvlan)
    |
    B (vlan)
    |
    C (bridge)
    |
    D (macvlan)
    |
    E (vlan)
    |
    F (bridge)

    A->lower_level : 6
    B->lower_level : 5
    C->lower_level : 4
    D->lower_level : 3
    E->lower_level : 2
    F->lower_level : 1

When an interface 'A' is removed, it releases resources.
At this moment, netif_addr_lock() would be called.
Then, netdev_upper_dev_unlink() is called recursively.
Then dev->lower_level is updated.
There is no problem.

But, when the bridge module is removed, 'C' and 'F' interfaces
are removed at once.
If 'F' is removed first, a lower_level value is like below.
    A->lower_level : 5
    B->lower_level : 4
    C->lower_level : 3
    D->lower_level : 2
    E->lower_level : 1
    F->lower_level : 1

Then, 'C' is removed. at this moment, netif_addr_lock() is called
recursively.
The ordering is like this.
C(3)->D(2)->E(1)->F(1)
At this moment, the lower_level value of 'E' and 'F' are the same.
So, lockdep warns a possible deadlock scenario.

In order to avoid this problem, a new variable 'nested_level' is added.
This value is the same as dev->lower_level - 1.
But this value is updated in rtnl_unlock().
So, this variable can be used as a parameter of spin_lock_nested() safely
in the rtnl context.

Test commands:
   ip link add br0 type bridge vlan_filtering 1
   ip link add vlan1 link br0 type vlan id 10
   ip link add macvlan2 link vlan1 type macvlan
   ip link add br3 type bridge vlan_filtering 1
   ip link set macvlan2 master br3
   ip link add vlan4 link br3 type vlan id 10
   ip link add macvlan5 link vlan4 type macvlan
   ip link add br6 type bridge vlan_filtering 1
   ip link set macvlan5 master br6
   ip link add vlan7 link br6 type vlan id 10
   ip link add macvlan8 link vlan7 type macvlan

   ip link set br0 up
   ip link set vlan1 up
   ip link set macvlan2 up
   ip link set br3 up
   ip link set vlan4 up
   ip link set macvlan5 up
   ip link set br6 up
   ip link set vlan7 up
   ip link set macvlan8 up
   modprobe -rv bridge

Splat looks like:
[   36.057436][  T744] WARNING: possible recursive locking detected
[   36.058848][  T744] 5.9.0-rc6+ #728 Not tainted
[   36.059959][  T744] --------------------------------------------
[   36.061391][  T744] ip/744 is trying to acquire lock:
[   36.062590][  T744] ffff8c4767509280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_set_rx_mode+0x19/0x30
[   36.064922][  T744]
[   36.064922][  T744] but task is already holding lock:
[   36.066626][  T744] ffff8c4767769280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_uc_add+0x1e/0x60
[   36.068851][  T744]
[   36.068851][  T744] other info that might help us debug this:
[   36.070731][  T744]  Possible unsafe locking scenario:
[   36.070731][  T744]
[   36.072497][  T744]        CPU0
[   36.073238][  T744]        ----
[   36.074007][  T744]   lock(&vlan_netdev_addr_lock_key);
[   36.075290][  T744]   lock(&vlan_netdev_addr_lock_key);
[   36.076590][  T744]
[   36.076590][  T744]  *** DEADLOCK ***
[   36.076590][  T744]
[   36.078515][  T744]  May be due to missing lock nesting notation
[   36.078515][  T744]
[   36.080491][  T744] 3 locks held by ip/744:
[   36.081471][  T744]  #0: ffffffff98571df0 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x236/0x490
[   36.083614][  T744]  #1: ffff8c4767769280 (&vlan_netdev_addr_lock_key){+...}-{2:2}, at: dev_uc_add+0x1e/0x60
[   36.085942][  T744]  #2: ffff8c476c8da280 (&bridge_netdev_addr_lock_key/4){+...}-{2:2}, at: dev_uc_sync+0x39/0x80
[   36.088400][  T744]
[   36.088400][  T744] stack backtrace:
[   36.089772][  T744] CPU: 6 PID: 744 Comm: ip Not tainted 5.9.0-rc6+ #728
[   36.091364][  T744] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[   36.093630][  T744] Call Trace:
[   36.094416][  T744]  dump_stack+0x77/0x9b
[   36.095385][  T744]  __lock_acquire+0xbc3/0x1f40
[   36.096522][  T744]  lock_acquire+0xb4/0x3b0
[   36.097540][  T744]  ? dev_set_rx_mode+0x19/0x30
[   36.098657][  T744]  ? rtmsg_ifinfo+0x1f/0x30
[   36.099711][  T744]  ? __dev_notify_flags+0xa5/0xf0
[   36.100874][  T744]  ? rtnl_is_locked+0x11/0x20
[   36.101967][  T744]  ? __dev_set_promiscuity+0x7b/0x1a0
[   36.103230][  T744]  _raw_spin_lock_bh+0x38/0x70
[   36.104348][  T744]  ? dev_set_rx_mode+0x19/0x30
[   36.105461][  T744]  dev_set_rx_mode+0x19/0x30
[   36.106532][  T744]  dev_set_promiscuity+0x36/0x50
[   36.107692][  T744]  __dev_set_promiscuity+0x123/0x1a0
[   36.108929][  T744]  dev_set_promiscuity+0x1e/0x50
[   36.110093][  T744]  br_port_set_promisc+0x1f/0x40 [bridge]
[   36.111415][  T744]  br_manage_promisc+0x8b/0xe0 [bridge]
[   36.112728][  T744]  __dev_set_promiscuity+0x123/0x1a0
[   36.113967][  T744]  ? __hw_addr_sync_one+0x23/0x50
[   36.115135][  T744]  __dev_set_rx_mode+0x68/0x90
[   36.116249][  T744]  dev_uc_sync+0x70/0x80
[   36.117244][  T744]  dev_uc_add+0x50/0x60
[   36.118223][  T744]  macvlan_open+0x18e/0x1f0 [macvlan]
[   36.119470][  T744]  __dev_open+0xd6/0x170
[   36.120470][  T744]  __dev_change_flags+0x181/0x1d0
[   36.121644][  T744]  dev_change_flags+0x23/0x60
[   36.122741][  T744]  do_setlink+0x30a/0x11e0
[   36.123778][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.124929][  T744]  ? __nla_validate_parse.part.6+0x45/0x8e0
[   36.126309][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.127457][  T744]  __rtnl_newlink+0x546/0x8e0
[   36.128560][  T744]  ? lock_acquire+0xb4/0x3b0
[   36.129623][  T744]  ? deactivate_slab.isra.85+0x6a1/0x850
[   36.130946][  T744]  ? __lock_acquire+0x92c/0x1f40
[   36.132102][  T744]  ? lock_acquire+0xb4/0x3b0
[   36.133176][  T744]  ? is_bpf_text_address+0x5/0xe0
[   36.134364][  T744]  ? rtnl_newlink+0x2e/0x70
[   36.135445][  T744]  ? rcu_read_lock_sched_held+0x32/0x60
[   36.136771][  T744]  ? kmem_cache_alloc_trace+0x2d8/0x380
[   36.138070][  T744]  ? rtnl_newlink+0x2e/0x70
[   36.139164][  T744]  rtnl_newlink+0x47/0x70
[ ... ]

Fixes: 845e0ebb ("net: change addr_list_lock back to static key")
Signed-off-by: default avatarTaehee Yoo <ap420073@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1fc70edb
    • Taehee Yoo's avatar
      net: core: introduce struct netdev_nested_priv for nested interface infrastructure · eff74233
      Taehee Yoo authored 
      Functions related to nested interface infrastructure such as
netdev_walk_all_{ upper | lower }_dev() pass both private functions
and "data" pointer to handle their own things.
At this point, the data pointer type is void *.
In order to make it easier to expand common variables and functions,
this new netdev_nested_priv structure is added.

In the following patch, a new member variable will be added into this
struct to fix the lockdep issue.
Signed-off-by: default avatarTaehee Yoo <ap420073@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      eff74233
    • Taehee Yoo's avatar
      net: core: add __netdev_upper_dev_unlink() · fe8300fd
      Taehee Yoo authored 
      The netdev_upper_dev_unlink() has to work differently according to flags.
This idea is the same with __netdev_upper_dev_link().

In the following patches, new flags will be added.
Signed-off-by: default avatarTaehee Yoo <ap420073@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      fe8300fd
    • Cong Wang's avatar
      net_sched: remove a redundant goto chain check · 1aad8049
      Cong Wang authored 
      All TC actions call tcf_action_check_ctrlact() to validate
goto chain, so this check in tcf_action_init_1() is actually
redundant. Remove it to save troubles of leaking memory.

Fixes: e49d8c22 ("net_sched: defer tcf_idr_insert() in tcf_action_init_1()")
Reported-by: default avatarVlad Buslov <vladbu@mellanox.com>
Suggested-by: default avatarDavide Caratti <dcaratti@redhat.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: default avatarDavide Caratti <dcaratti@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      1aad8049
    • Nikolay Aleksandrov's avatar
      net: bridge: fdb: don't flush ext_learn entries · f2f3729f
      Nikolay Aleksandrov authored 
      When a user-space software manages fdb entries externally it should
set the ext_learn flag which marks the fdb entry as externally managed
and avoids expiring it (they're treated as static fdbs). Unfortunately
on events where fdb entries are flushed (STP down, netlink fdb flush
etc) these fdbs are also deleted automatically by the bridge. That in turn
causes trouble for the managing user-space software (e.g. in MLAG setups
we lose remote fdb entries on port flaps).
These entries are completely externally managed so we should avoid
automatically deleting them, the only exception are offloaded entries
(i.e. BR_FDB_ADDED_BY_EXT_LEARN + BR_FDB_OFFLOADED). They are flushed as
before.

Fixes: eb100e0e ("net: bridge: allow to add externally learned entries from user-space")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f2f3729f
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