[SRU][Trusty][Vivid][Wily][PATCH 0/1] tcp: fix recv with flags MSG_WAITALL | MSG_PEEK

[Joseph Salisbury]

BugLink: http://bugs.launchpad.net/bugs/1486146


== SRU Justification ==
In a multi-threaded pthreads process running on Ubuntu (with over 1000
threads) which uses real time FIFO scheduling, occasionally it is seen that calls to recv()
with flags (MSG_PEEK | MSG_WAITALL) get stuck in an infinte loop or deadlock meaning 
the threads lock up chewing as much CPU as they can (due to FIFO scheduling) while 
stuck inside recv().

This is fixed by commit dfbafc995, which is in mainline as of v4.2-rc5.  However, the commit
was not cc'd to stable, so requesting a SRU.

This commit does not pick cleanly to Precise, so not requesting it there.


== Fix ==
commit dfbafc995304ebb9a9b03f65083e6e9cea143b20
Author: Sabrina Dubroca <sd at queasysnail.net>
Date:   Fri Jul 24 18:19:25 2015 +0200

    tcp: fix recv with flags MSG_WAITALL | MSG_PEEK



== Test Case ==
A test kernel was built with this patch and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.




Sabrina Dubroca (1):
  tcp: fix recv with flags MSG_WAITALL | MSG_PEEK

 include/net/sock.h |  2 +-
 net/core/sock.c    |  5 +++--
 net/dccp/proto.c   |  2 +-
 net/ipv4/tcp.c     | 11 +++++++----
 net/llc/af_llc.c   |  4 ++--
 5 files changed, 14 insertions(+), 10 deletions(-)

-- 
2.1.0