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  1. 04 Feb, 2011 1 commit
    • David S. Miller's avatar
      niu: Fix races between up/down and get_stats. · 9690c636
      David S. Miller authored 
      As reported by Flavio Leitner, there is no synchronization to protect
NIU's get_stats method from seeing a NULL pointer in either
np->rx_rings or np->tx_rings.  In fact, as far as ->ndo_get_stats
is concerned, these values are set completely asynchronously.

Flavio attempted to fix this using a RW semaphore, which in fact
works most of the time.  However, dev_get_stats() can be invoked
from non-sleepable contexts in some cases, so this fix doesn't
work in all cases.

So instead, control the visibility of the np->{rx,tx}_ring pointers
when the device is being brough up, and use properties of the device
down sequence to our advantage.

In niu_get_stats(), return immediately if netif_running() is false.
The device shutdown sequence first marks the device as not running (by
clearing the __LINK_STATE_START bit), then it performans a
synchronize_rcu() (in dev_deactive_many()), and then finally it
invokes the driver ->ndo_stop() method.

This guarentees that all invocations of niu_get_stats() either see
netif_running() as false, or they see the channel pointers before
->ndo_stop() clears them out.

If netif_running() is true, protect against startup races by loading
the np->{rx,tx}_rings pointer into a local variable, and punting if
it is NULL.  Use ACCESS_ONCE to prevent the compiler from reloading
the pointer on us.

Also, during open, control the order in which the pointers and the
ring counts become visible globally using SMP write memory barriers.
We make sure the np->num_{rx,tx}_rings value is stable and visible
before np->{rx,tx}_rings is.

Such visibility control is not necessary on the niu_free_channels()
side because of the RCU sequencing that happens during device down as
described above.  We are always guarenteed that all niu_get_stats
calls are finished, or will see netif_running() false, by the time
->ndo_stop is invoked.
Reported-by: default avatarFlavio Leitner <fleitner@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      9690c636
  3. 02 Feb, 2011 10 commits
  5. 01 Feb, 2011 16 commits
  7. 31 Jan, 2011 9 commits
  9. 30 Jan, 2011 4 commits
    • Sven Eckelmann's avatar
      batman-adv: Make vis info stack traversal threadsafe · 1181e1da
      Sven Eckelmann authored 
      The batman-adv vis server has to a stack which stores all information
about packets which should be send later. This stack is protected
with a spinlock that is used to prevent concurrent write access to it.

The send_vis_packets function has to take all elements from the stack
and send them to other hosts over the primary interface. The send will
be initiated without the lock which protects the stack.

The implementation using list_for_each_entry_safe has the problem that
it stores the next element as "safe ptr" to allow the deletion of the
current element in the list. The list may be modified during the
unlock/lock pair in the loop body which may make the safe pointer
not pointing to correct next element.

It is safer to remove and use the first element from the stack until no
elements are available. This does not need reduntant information which
would have to be validated each time the lock was removed.
Reported-by: default avatarRussell Senior <russell@personaltelco.net>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
      1181e1da
    • Sven Eckelmann's avatar
      batman-adv: Remove vis info element in free_info · dda9fc6b
      Sven Eckelmann authored 
      The free_info function will be called when no reference to the info
object exists anymore. It must be ensured that the allocated memory
gets freed and not only the elements which are managed by the info
object.
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
      dda9fc6b
    • Sven Eckelmann's avatar
      batman-adv: Remove vis info on hashing errors · 2674c158
      Sven Eckelmann authored 
      A newly created vis info object must be removed when it couldn't be
added to the hash. The old_info which has to be replaced was already
removed and isn't related to the hash anymore.
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
      2674c158
    • Eric W. Biederman's avatar
      net: Add compat ioctl support for the ipv4 multicast ioctl SIOCGETSGCNT · 709b46e8
      Eric W. Biederman authored 
      SIOCGETSGCNT is not a unique ioctl value as it it maps tio SIOCPROTOPRIVATE +1,
which unfortunately means the existing infrastructure for compat networking
ioctls is insufficient.  A trivial compact ioctl implementation would conflict
with:

SIOCAX25ADDUID
SIOCAIPXPRISLT
SIOCGETSGCNT_IN6
SIOCGETSGCNT
SIOCRSSCAUSE
SIOCX25SSUBSCRIP
SIOCX25SDTEFACILITIES

To make this work I have updated the compat_ioctl decode path to mirror the
the normal ioctl decode path.  I have added an ipv4 inet_compat_ioctl function
so that I can have ipv4 specific compat ioctls.   I have added a compat_ioctl
function into struct proto so I can break out ioctls by which kind of ip socket
I am using.  I have added a compat_raw_ioctl function because SIOCGETSGCNT only
works on raw sockets.  I have added a ipmr_compat_ioctl that mirrors the normal
ipmr_ioctl.

This was necessary because unfortunately the struct layout for the SIOCGETSGCNT
has unsigned longs in it so changes between 32bit and 64bit kernels.

This change was sufficient to run a 32bit ip multicast routing daemon on a
64bit kernel.
Reported-by: default avatarBill Fenner <fenner@aristanetworks.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      709b46e8
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