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  1. 21 Apr, 2012 2 commits
    • Wenqi Ma's avatar
      net/hyperv: Adding cancellation to ensure rndis filter is closed · 792df872
      Wenqi Ma authored 
      Although the network interface is down, the RX packets number which
could be observed by ifconfig may keep on increasing.

This is because the WORK scheduled in netvsc_set_multicast_list()
may be executed after netvsc_close(). That means the rndis filter
may be re-enabled by do_set_multicast() even if it was closed by
netvsc_close().

By canceling possible WORK before close the rndis filter, the issue
could be never happened.
Signed-off-by: default avatarWenqi Ma <wenqi_ma@trendmicro.com.cn>
Reviewed-by: default avatarWei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      792df872
    • Stephen Boyd's avatar
      ks8851: Fix mutex deadlock in ks8851_net_stop() · c5a99937
      Stephen Boyd authored 
      There is a potential deadlock scenario when the ks8851 driver
is removed. The interrupt handler schedules a workqueue which
acquires a mutex that ks8851_net_stop() also acquires before
flushing the workqueue. Previously lockdep wouldn't be able
to find this problem but now that it has the support we can
trigger this lockdep warning by rmmoding the driver after
an ifconfig up.

Fix the possible deadlock by disabling the interrupts in
the chip and then release the lock across the workqueue
flushing. The mutex is only there to proect the registers
anyway so this should be ok.

=======================================================
[ INFO: possible circular locking dependency detected ]
3.0.21-00021-g8b33780-dirty #2911
-------------------------------------------------------
rmmod/125 is trying to acquire lock:
 ((&ks->irq_work)){+.+...}, at: [<c019e0b8>] flush_work+0x0/0xac

but task is already holding lock:
 (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&ks->lock){+.+...}:
       [<c01b89c8>] __lock_acquire+0x940/0x9f8
       [<c01b9058>] lock_acquire+0x10c/0x130
       [<c083dbec>] mutex_lock_nested+0x68/0x3dc
       [<bf00bd48>] ks8851_irq_work+0x24/0x46c [ks8851]
       [<c019c580>] process_one_work+0x2d8/0x518
       [<c019cb98>] worker_thread+0x220/0x3a0
       [<c01a2ad4>] kthread+0x88/0x94
       [<c0107008>] kernel_thread_exit+0x0/0x8

-> #0 ((&ks->irq_work)){+.+...}:
       [<c01b7984>] validate_chain+0x914/0x1018
       [<c01b89c8>] __lock_acquire+0x940/0x9f8
       [<c01b9058>] lock_acquire+0x10c/0x130
       [<c019e104>] flush_work+0x4c/0xac
       [<bf00b858>] ks8851_net_stop+0x6c/0x138 [ks8851]
       [<c06b209c>] __dev_close_many+0x98/0xcc
       [<c06b2174>] dev_close_many+0x68/0xd0
       [<c06b22ec>] rollback_registered_many+0xcc/0x2b8
       [<c06b2554>] rollback_registered+0x28/0x34
       [<c06b25b8>] unregister_netdevice_queue+0x58/0x7c
       [<c06b25f4>] unregister_netdev+0x18/0x20
       [<bf00c1f4>] ks8851_remove+0x64/0xb4 [ks8851]
       [<c049ddf0>] spi_drv_remove+0x18/0x1c
       [<c0468e98>] __device_release_driver+0x7c/0xbc
       [<c0468f64>] driver_detach+0x8c/0xb4
       [<c0467f00>] bus_remove_driver+0xb8/0xe8
       [<c01c1d20>] sys_delete_module+0x1e8/0x27c
       [<c0105ec0>] ret_fast_syscall+0x0/0x3c

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ks->lock);
                               lock((&ks->irq_work));
                               lock(&ks->lock);
  lock((&ks->irq_work));

 *** DEADLOCK ***

4 locks held by rmmod/125:
 #0:  (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f44>] driver_detach+0x6c/0xb4
 #1:  (&__lockdep_no_validate__){+.+.+.}, at: [<c0468f50>] driver_detach+0x78/0xb4
 #2:  (rtnl_mutex){+.+.+.}, at: [<c06b25e8>] unregister_netdev+0xc/0x20
 #3:  (&ks->lock){+.+...}, at: [<bf00b850>] ks8851_net_stop+0x64/0x138 [ks8851]

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      c5a99937
  3. 19 Apr, 2012 5 commits
  5. 18 Apr, 2012 12 commits
  7. 17 Apr, 2012 10 commits
  9. 16 Apr, 2012 2 commits
  11. 14 Apr, 2012 3 commits
  13. 13 Apr, 2012 6 commits
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