Commit Graph

2600 Commits

Author SHA1 Message Date
Kirill Korotaev
3fcde74b38 [NEIGH]: neigh_table_clear() doesn't free stats
neigh_table_clear() doesn't free tbl->stats.
Found by Alexey Kuznetsov. Though Alexey considers this
leak minor for mainstream, I still believe that cleanup
code should not forget to free some of the resources :)

At least, this is critical for OpenVZ with virtualized
neighbour tables.

Signed-Off-By: Kirill Korotaev <dev@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-09-17 23:21:01 -07:00
Wei Dong
0668b47205 [IPV4]: Fix SNMPv2 "ipFragFails" counter error
When I tested Linux kernel 2.6.17.7 about statistics
"ipFragFails",found that this counter couldn't increase correctly. The
criteria is RFC2011:
RFC2011
  ipFragFails OBJECT-TYPE
    SYNTAX      Counter32
    MAX-ACCESS  read-only
    STATUS      current
    DESCRIPTION
            "The number of IP datagrams that have been discarded because
            they needed to be fragmented at this entity but could not
            be, e.g., because their Don't Fragment flag was set."
    ::= { ip 18 }

When I send big IP packet to a router with DF bit set to 1 which need to
be fragmented, and router just sends an ICMP error message
ICMP_FRAG_NEEDED but no increments for this counter(in the function
ip_fragment).

Signed-off-by: Wei Dong <weid@nanjing-fnst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-31 15:24:48 -07:00
Akinobu Mita
5991c84421 [NET]: Rate limiting for socket allocation failure messages.
This patch limits the warning messages when socket allocation failures
happen. It happens under memory pressure.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-31 15:21:50 -07:00
YOSHIFUJI Hideaki
99c7bc0133 [IPV6]: Fix kernel OOPs when setting sticky socket options.
Bug noticed by Remi Denis-Courmont <rdenis@simphalempin.com>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-31 14:52:17 -07:00
Keir Fraser
57f5f544f5 [IPV6]: ipv6_add_addr should install dstentry earlier
ipv6_add_addr allocates a struct inet6_ifaddr and a dstentry, but it
doesn't install the dstentry in ifa->rt until after it releases the
addrconf_hash_lock. This means other CPUs will be able to see the new
address while it hasn't been initialized completely yet.

One possible fix would be to grab the ifp->lock spinlock when
creating the address struct; a simpler fix is to just move the
assignment.

Acked-by: jbeulich@novell.com
Acked-by: okir@suse.de
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:18 -07:00
Akinobu Mita
fab2caf62e [NETLINK]: Call panic if nl_table allocation fails
This patch makes crash happen if initialization of nl_table fails
in initcalls. It is better than getting use after free crash later.

Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:18 -07:00
Daikichi Osuga
3fdf3f0c99 [TCP]: Two RFC3465 Appropriate Byte Count fixes.
1) fix slow start after retransmit timeout
2) fix case of L=2*SMSS acked bytes comparison

Signed-off-by: Daikichi Osuga <osugad@s1.nttdocomo.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:16 -07:00
Lv Liangying
76d0cc1b64 [IPV6]: SNMPv2 "ipv6IfStatsInAddrErrors" counter error
When I tested Linux kernel 2.6.17.7 about statistics
"ipv6IfStatsInAddrErrors", found that this counter couldn't increase
correctly. The criteria is RFC2465:
 ipv6IfStatsInAddrErrors OBJECT-TYPE
      SYNTAX      Counter32
      MAX-ACCESS  read-only
      STATUS      current
      DESCRIPTION
         "The number of input datagrams discarded because
         the IPv6 address in their IPv6 header's destination
         field was not a valid address to be received at
         this entity.  This count includes invalid
         addresses (e.g., ::0) and unsupported addresses
         (e.g., addresses with unallocated prefixes).  For
         entities which are not IPv6 routers and therefore
         do not forward datagrams, this counter includes
         datagrams discarded because the destination address
         was not a local address."
      ::= { ipv6IfStatsEntry 5 }

When I send packet to host with destination that is ether invalid
address(::0) or unsupported addresses(1::1), the Linux kernel just
discard the packet, and the counter doesn't increase(in the function
ip6_pkt_discard).

Signed-off-by: Lv Liangying <lvly@nanjing-fnst.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:15 -07:00
Sridhar Samudrala
b9ac86727f [SCTP]: Fix sctp_primitive_ABORT() call in sctp_close().
With the recent fix, the callers of sctp_primitive_ABORT()
need to create an ABORT chunk and pass it as an argument rather
than msghdr that was passed earlier.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-29 21:22:13 -07:00
Ian McDonald
66a377c504 [DCCP]: Fix CCID3
This fixes CCID3 to give much closer performance to RFC4342.

CCID3 is meant to alter sending rate based on RTT and loss.

The performance was verified against:
http://wand.net.nz/~perry/max_download.php

For example I tested with netem and had the following parameters:
Delayed Acks 1, MSS 256 bytes, RTT 105 ms, packet loss 5%.

This gives a theoretical speed of 71.9 Kbits/s. I measured across three
runs with this patch set and got 70.1 Kbits/s. Without this patchset the
average was 232 Kbits/s which means Linux can't be used for CCID3 research
properly.

I also tested with netem turned off so box just acting as router with 1.2
msec RTT. The performance with this is the same with or without the patch
at around 30 Mbit/s.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 23:40:50 -07:00
Stephen Hemminger
3a13813e6e [BRIDGE] netfilter: memory corruption fix
The bridge-netfilter code will overwrite memory if there is not
headroom in the skb to save the header.  This first showed up when
using Xen with sky2 driver that doesn't allocate the extra space.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 20:28:30 -07:00
Ian McDonald
80193aee18 [DCCP]: Introduce dccp_rx_hist_find_entry
This adds a new function dccp_rx_hist_find_entry.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 19:07:36 -07:00
Ian McDonald
837d107cd1 [DCCP]: Introduces follows48 function
This adds a new function to see if two sequence numbers follow each
other.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 19:06:42 -07:00
Ian McDonald
e6bccd3573 [DCCP]: Update contact details and copyright
Just updating copyright and contacts

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 19:01:30 -07:00
Ian McDonald
f3166c0717 [DCCP]: Fix typo
This fixes a small typo in net/dccp/libs/packet_history.c

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 19:01:03 -07:00
Stephen Hemminger
59eed279c5 [IPV6]: Segmentation offload not set correctly on TCP children
TCP over IPV6 would incorrectly inherit the GSO settings.
This would cause kernel to send Tcp Segmentation Offload packets for
IPV6 data to devices that can't handle it. It caused the sky2 driver
to lock http://bugzilla.kernel.org/show_bug.cgi?id=7050
and the e1000 would generate bogus packets. I can't blame the
hardware for gagging if the upper layers feed it garbage.

This was a new bug in 2.6.18 introduced with GSO support.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-26 18:42:01 -07:00
Greg Kroah-Hartman
62250b3bb5 Merge branch 'fixes' of git://git.linux-nfs.org/pub/linux/nfs-2.6 2006-08-24 22:29:46 -07:00
David Howells
e8896495bc NFS: Check lengths more thoroughly in NFS4 readdir XDR decode
Check the bounds of length specifiers more thoroughly in the XDR decoding of
NFS4 readdir reply data.

Currently, if the server returns a bitmap or attr length that causes the
current decode point pointer to wrap, this could go undetected (consider a
small "negative" length on a 32-bit machine).

Also add a check into the main XDR decode handler to make sure that the amount
of data is a multiple of four bytes (as specified by RFC-1014).  This makes
sure that we can do u32* pointer subtraction in the NFS client without risking
an undefined result (the result is undefined if the pointers are not correctly
aligned with respect to one another).

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 5861fddd64a7eaf7e8b1a9997455a24e7f688092 commit)
2006-08-24 15:53:34 -04:00
Trond Myklebust
8f8e7a50f4 SUNRPC: Fix dentry refcounting issues with users of rpc_pipefs
rpc_unlink() and rpc_rmdir() will dput the dentry reference for you.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from a05a57effa71a1f67ccbfc52335c10c8b85f3f6a commit)
2006-08-24 15:50:51 -04:00
Trond Myklebust
68adb0af51 SUNRPC: rpc_unlink() must check for unhashed dentries
A prior call to rpc_depopulate() by rpc_rmdir() on the parent directory may
have already called simple_unlink() on this entry.
Add the same check to rpc_rmdir(). Also remove a redundant call to
rpc_close_pipes() in rpc_rmdir.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 0bbfb9d20f6437c4031aa3bf9b4d311a053e58e3 commit)
2006-08-24 15:50:42 -04:00
Trond Myklebust
dff02cc1a3 NFS: clean up rpc_rmdir
Make it take a dentry argument instead of a path

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 648d4116eb2509f010f7f34704a650150309b3e7 commit)
2006-08-24 15:50:32 -04:00
Trond Myklebust
5d67476fff SUNRPC: make rpc_unlink() take a dentry argument instead of a path
Signe-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
(cherry picked from 88bf6d811b01a4be7fd507d18bf5f1c527989089 commit)
2006-08-24 15:50:07 -04:00
Stephen Hemminger
316c1592be [TCP]: Limit window scaling if window is clamped.
This small change allows for easy per-route workarounds for broken hosts or
middleboxes that are not compliant with TCP standards for window scaling.
Rather than having to turn off window scaling globally. This patch allows
reducing or disabling window scaling if window clamp is present.

Example: Mark Lord reported a problem with 2.6.17 kernel being unable to
access http://www.everymac.com

# ip route add 216.145.246.23/32 via 10.8.0.1 window 65535

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-22 14:33:57 -07:00
Patrick McHardy
e0b7cde997 [NETFILTER]: arp_tables: fix table locking in arpt_do_table
table->private might change because of ruleset changes, don't use it
without holding the lock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-22 14:33:56 -07:00
Sridhar Samudrala
c164a9ba0a Fix sctp privilege elevation (CVE-2006-3745)
sctp_make_abort_user() now takes the msg_len along with the msg
so that we don't have to recalculate the bytes in iovec.
It also uses memcpy_fromiovec() so that we don't go beyond the
length allocated.

It is good to have this fix even if verify_iovec() is fixed to
return error on overflow.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-08-22 12:52:23 -07:00
Herbert Xu
78eb887733 [BRIDGE]: Disable SG/GSO if TX checksum is off
When the bridge recomputes features, it does not maintain the
constraint that SG/GSO must be off if TX checksum is off.
This patch adds that constraint.

On a completely unrelated note, I've also added TSO6 and TSO_ECN
feature bits if GSO is enabled on the underlying device through
the new NETIF_F_GSO_SOFTWARE macro.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 18:22:32 -07:00
Patrick McHardy
8311731afc [NETFILTER]: ip_tables: fix table locking in ipt_do_table
table->private might change because of ruleset changes, don't use it without
holding the lock.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 18:13:53 -07:00
Patrick McHardy
d205dc4079 [NETFILTER]: ctnetlink: fix deadlock in table dumping
ip_conntrack_put must not be called while holding ip_conntrack_lock
since destroy_conntrack takes it again.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 18:12:38 -07:00
Alexey Kuznetsov
6e8fcbf640 [IPV4]: severe locking bug in fib_semantics.c
Found in 2.4 by Yixin Pan <yxpan@hotmail.com>.

> When I read fib_semantics.c of Linux-2.4.32, write_lock(&fib_info_lock) =
> is used in fib_release_info() instead of write_lock_bh(&fib_info_lock).  =
> Is the following case possible: a BH interrupts fib_release_info() while =
> holding the write lock, and calls ip_check_fib_default() which calls =
> read_lock(&fib_info_lock), and spin forever.

Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:44:46 -07:00
David L Stevens
acd6e00b8e [MCAST]: Fix filter leak on device removal.
This fixes source filter leakage when a device is removed and a
process leaves the group thereafter.

This also includes corresponding fixes for IPv6 multicast source
filters on device removal.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:57 -07:00
David S. Miller
c7fa9d189e [NET]: Disallow whitespace in network device names.
It causes way too much trouble and confusion in userspace.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:56 -07:00
Ralf Hildebrandt
c0956bd251 [PKT_SCHED] cls_u32: Fix typo.
Signed-off-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:54 -07:00
Kevin Hilman
b9c6e3e966 [ATM]: Compile error on ARM
atm_proc_exit() is declared as __exit, and thus in .exit.text.  On
some architectures (ARM) .exit.text is discarded at compile time, and
since atm_proc_exit() is called by some other __init functions, it
results in a link error.

Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:53 -07:00
Michal Ruzicka
bb699cbca0 [IPV4]: Possible leak of multicast source filter sctructure
There is a leak of a socket's multicast source filter list structure
on closing a socket with a multicast source filter set on an interface
that does not exist any more.

Signed-off-by: Michal Ruzicka <michal.ruzicka@comstar.cz>
Acked-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:49 -07:00
Ingo Molnar
640c41c77a [IPV6] lockdep: annotate __icmpv6_socket
Split off __icmpv6_socket's sk->sk_dst_lock class, because it gets
used from softirqs, which is safe for __icmpv6_sockets (because they
never get directly used via userspace syscalls), but unsafe for normal
sockets.

Has no effect on non-lockdep kernels.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:48 -07:00
Andrew Morton
deb47c66e1 [NETFILTER]: xt_physdev build fix
It needs netfilter_bridge.h for brnf_deferred_hooks

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:47 -07:00
Suresh Siddha
8557511250 [NET]: Fix potential stack overflow in net/core/utils.c
On High end systems (1024 or so cpus) this can potentially cause stack
overflow.  Fix the stack usage.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:47 -07:00
David S. Miller
7ea49ed73c [VLAN]: Make sure bonding packet drop checks get done in hwaccel RX path.
Since __vlan_hwaccel_rx() is essentially bypassing the
netif_receive_skb() call that would have occurred if we did the VLAN
decapsulation in software, we are missing the skb_bond() call and the
assosciated checks it does.

Export those checks via an inline function, skb_bond_should_drop(),
and use this in __vlan_hwaccel_rx().

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-17 16:29:46 -07:00
Herbert Xu
e9fa4f7bd2 [INET]: Use pskb_trim_unique when trimming paged unique skbs
The IPv4/IPv6 datagram output path was using skb_trim to trim paged
packets because they know that the packet has not been cloned yet
(since the packet hasn't been given to anything else in the system).

This broke because skb_trim no longer allows paged packets to be
trimmed.  Paged packets must be given to one of the pskb_trim functions
instead.

This patch adds a new pskb_trim_unique function to cover the IPv4/IPv6
datagram output path scenario and replaces the corresponding skb_trim
calls with it.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 20:12:58 -07:00
Mark Huang
dcb7cd97f1 [NETFILTER]: ulog: fix panic on SMP kernels
Fix kernel panic on various SMP machines. The culprit is a null
ub->skb in ulog_send(). If ulog_timer() has already been scheduled on
one CPU and is spinning on the lock, and ipt_ulog_packet() flushes the
queue on another CPU by calling ulog_send() right before it exits,
there will be no skbuff when ulog_timer() acquires the lock and calls
ulog_send(). Cancelling the timer in ulog_send() doesn't help because
it has already been scheduled and is running on the first CPU.

Similar problem exists in ebt_ulog.c and nfnetlink_log.c.

Signed-off-by: Mark Huang <mlhuang@cs.princeton.edu>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:57:54 -07:00
Patrick McHardy
0eff66e625 [NETFILTER]: {arp,ip,ip6}_tables: proper error recovery in init path
Neither of {arp,ip,ip6}_tables cleans up behind itself when something goes
wrong during initialization.

Noticed by Rennie deGraaf <degraaf@cpsc.ucalgary.ca>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:57:28 -07:00
Stephen Hemminger
7ee66fcb94 [LLC]: multicast receive device match
Fix from Aji_Srinivas@emc.com, STP packets are incorrectly received on
all LLC datagram sockets, whichever interface they are bound to.  The
llc_sap datagram receive logic sends packets with a unicast
destination MAC to one socket bound to that SAP and MAC, and multicast
packets to all sockets bound to that SAP. STP packets are multicast,
and we do need to know on which interface they were received.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:56:26 -07:00
David S. Miller
d49c73c729 [IPSEC]: Validate properly in xfrm_dst_check()
If dst->obsolete is -1, this is a signal from the
bundle creator that we want the XFRM dst and the
dsts that it references to be validated on every
use.

I misunderstood this intention when I changed
xfrm_dst_check() to always return NULL.

Now, when we purge a dst entry, by running dst_free()
on it.  This will set the dst->obsolete to a positive
integer, and we want to return NULL in that case so
that the socket does a relookup for the route.

Thus, if dst->obsolete<0, let stale_bundle() validate
the state, else always return NULL.

In general, we need to do things more intelligently
here because we flush too much state during rule
changes.  Herbert Xu has some ideas wherein the key
manager gives us some help in this area.  We can also
use smarter state management algorithms inside of
the kernel as well.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:55:53 -07:00
Patrick McHardy
1c7628bd7a [NETFILTER]: xt_hashlimit: fix limit off-by-one
Hashlimit doesn't account for the first packet, which is inconsistent
with the limit match.

Reported by ryan.castellucci@gmail.com, netfilter bugzilla #500.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:06:02 -07:00
Phil Oester
97c802a113 [NETFILTER]: xt_string: fix negation
The xt_string match is broken with ! negation.
This resolves a portion of netfilter bugzilla #497.

Signed-off-by: Phil Oester <kernel@linuxace.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:05:35 -07:00
David S. Miller
18b6fe64d4 [TCP]: Fix botched memory leak fix to tcpprobe_read().
Somehow I clobbered James's original fix and only my
subsequent compiler warning change went in for that
changeset.

Get the real fix in there.

Noticed by Jesper Juhl.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-13 18:05:09 -07:00
David S. Miller
fff642570d [IPX]: Fix typo, ipxhdr() --> ipx_hdr()
Noticed by Dave Jones.

Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-09 17:36:15 -07:00
Herbert Xu
06aebfb7fa [IPV6]: The ifa lock is a BH lock
The ifa lock is expected to be taken in BH context (by addrconf timers)
so we must disable BH when accessing it from user context.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-09 16:52:04 -07:00
Greg Kroah-Hartman
a465714109 Merge gregkh@master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 2006-08-09 11:49:13 -07:00
Dmitry Mishin
7c91767a6b [NET]: add_timer -> mod_timer() in dst_run_gc()
Patch from Dmitry Mishin <dim@openvz.org>:

Replace add_timer() by mod_timer() in dst_run_gc
in order to avoid BUG message.

       CPU1                            CPU2
dst_run_gc()  entered           dst_run_gc() entered
spin_lock(&dst_lock)                   .....
del_timer(&dst_gc_timer)         fail to get lock
       ....                         mod_timer() <--- puts 
                                                 timer back
                                                 to the list
add_timer(&dst_gc_timer) <--- BUG because timer is in list already.

Found during OpenVZ internal testing.

At first we thought that it is OpenVZ specific as we
added dst_run_gc(0) call in dst_dev_event(),
but as Alexey pointed to me it is possible to trigger
this condition in mainstream kernel.

F.e. timer has fired on CPU2, but the handler was preeempted
by an irq before dst_lock is tried.
Meanwhile, someone on CPU1 adds an entry to gc list and
starts the timer.
If CPU2 was preempted long enough, this timer can expire
simultaneously with resuming timer handler on CPU1, arriving
exactly to the situation described.

Signed-off-by: Dmitry Mishin <dim@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-08-09 02:25:54 -07:00