linux.git/net/sctp/input.c, branch v2.6.35

sctp: Fix a race between ICMP protocol unreachable and connect()

2010-05-06T07:56:07+00:00

ICMP protocol unreachable handling completely disregarded
the fact that the user may have locked the socket.  It proceeded
to destroy the association, even though the user may have
held the lock and had a ref on the association.  This resulted
in the following:

Attempt to release alive inet socket f6afcc00

=========================
[ BUG: held lock freed! ]
-------------------------
somenu/2672 is freeing memory f6afcc00-f6afcfff, with a lock still held
there!
 (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c
1 lock held by somenu/2672:
 #0:  (sk_lock-AF_INET){+.+.+.}, at: [] sctp_connect+0x13/0x4c

stack backtrace:
Pid: 2672, comm: somenu Not tainted 2.6.32-telco #55
Call Trace:
 [] ? printk+0xf/0x11
 [] debug_check_no_locks_freed+0xce/0xff
 [] kmem_cache_free+0x21/0x66
 [] __sk_free+0x9d/0xab
 [] sk_free+0x1c/0x1e
 [] sctp_association_put+0x32/0x89
 [] __sctp_connect+0x36d/0x3f4
 [] ? sctp_connect+0x13/0x4c
 [] ? autoremove_wake_function+0x0/0x33
 [] sctp_connect+0x31/0x4c
 [] inet_dgram_connect+0x4b/0x55
 [] sys_connect+0x54/0x71
 [] ? lock_release_non_nested+0x88/0x239
 [] ? might_fault+0x42/0x7c
 [] ? might_fault+0x42/0x7c
 [] sys_socketcall+0x6d/0x178
 [] ? trace_hardirqs_on_thunk+0xc/0x10
 [] syscall_call+0x7/0xb

This was because the sctp_wait_for_connect() would aqcure the socket
lock and then proceed to release the last reference count on the
association, thus cause the fully destruction path to finish freeing
the socket.

The simplest solution is to start a very short timer in case the socket
is owned by user.  When the timer expires, we can do some verification
and be able to do the release properly.

Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

net: backlog functions rename

2010-03-05T21:34:03+00:00

sk_add_backlog -> __sk_add_backlog
sk_add_backlog_limited -> sk_add_backlog

Signed-off-by: Zhu Yi 
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller

sctp: use limited socket backlog

2010-03-05T21:34:01+00:00

Make sctp adapt to the limited socket backlog change.

Cc: Vlad Yasevich 
Cc: Sridhar Samudrala 
Signed-off-by: Zhu Yi 
Signed-off-by: David S. Miller

sctp: Use frag list abstraction interfaces.

2009-06-09T07:24:07+00:00

Signed-off-by: David S. Miller

sctp: Clean up sctp checksumming code

2009-02-16T08:03:10+00:00

The sctp crc32c checksum is always generated in little endian.
So, we clean up the code to treat it as little endian and remove
all the __force casts.

Suggested by Herbert Xu.

Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Allow to disable SCTP checksums via module parameter

2009-02-16T08:03:09+00:00

This is a new version of my patch, now using a module parameter instead
of a sysctl, so that the option is harder to find. Please note that,
once the module is loaded, it is still possible to change the value of
the parameter in /sys/module/sctp/parameters/, which is useful if you
want to do performance comparisons without rebooting.

Computation of SCTP checksums significantly affects the performance of
SCTP. For example, using two dual-Opteron 246 connected using a Gbe
network, it was not possible to achieve more than ~730 Mbps, compared to
941 Mbps after disabling SCTP checksums.
Unfortunately, SCTP checksum offloading in NICs is not commonly
available (yet).

By default, checksums are still enabled, of course.

Signed-off-by: Lucas Nussbaum 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Fix another socket race during accept/peeloff

2009-01-22T22:53:23+00:00

There is a race between sctp_rcv() and sctp_accept() where we
have moved the association from the listening socket to the
accepted socket, but sctp_rcv() processing cached the old
socket and continues to use it.

The easy solution is to check for the socket mismatch once we've
grabed the socket lock.  If we hit a mis-match, that means
that were are currently holding the lock on the listening socket,
but the association is refrencing a newly accepted socket.  We need
to drop the lock on the old socket and grab the lock on the new one.

A more proper solution might be to create accepted sockets when
the new association is established, similar to TCP.  That would
eliminate the race for 1-to-1 style sockets, but it would still
existing for 1-to-many sockets where a user wished to peeloff an
association.  For now, we'll live with this easy solution as
it addresses the problem.

Reported-by: Michal Hocko 
Reported-by: Karsten Keil 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: Drop ICMP packet too big message with MTU larger than current PMTU

2008-10-23T07:59:52+00:00

If ICMP packet too big message is received with MTU larger than current
PMTU, SCTP will still accept this ICMP message and sync the PMTU of assoc
with the wrong MTU.

Endpoing A                 Endpoint B
(ESTABLISHED)              (ESTABLISHED)
ICMP         --------->
(packet too big, MTU too larger)
                           sync PMTU

This patch fixed the problem by drop that ICMP message.

Signed-off-by: Wei Yongjun 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller

sctp: remove unnecessary byteshifting, calculate directly in big-endian

2008-07-19T06:07:09+00:00

Signed-off-by: Harvey Harrison 
Signed-off-by: Vlad Yasevich 
Signed-off-by: David S. Miller