142d151f07
When I type in 'quit' on the slave instance, the master instance crashes
on this line.
0: /home/sluong/vpp-master/vpp/build-data/../src/vlib/unix/input.c:200 (linux_epoll_input) assertion `! pool_is_free (um->file_pool, _e)' fails
Aborted (core dumped)
Below is the decode from gdb
line_number=0, fmt=0x7f57af6cc9a0 "%s:%d (%s) assertion `%s' fails")
at /home/sluong/vpp-master/vpp/build-data/../src/vppinfra/error.c:143
vm=0x7f57af8e2400 <vlib_global_main>, node=0x7f576d40ad80, frame=0x0)
at /home/sluong/vpp-master/vpp/build-data/../src/vlib/unix/input.c:200
vm=0x7f57af8e2400 <vlib_global_main>, node=0x7f576d40ad80,
type=VLIB_NODE_TYPE_PRE_INPUT, dispatch_state=VLIB_NODE_STATE_POLLING,
frame=0x0, last_time_stamp=1525665215050617)
at /home/sluong/vpp-master/vpp/build-data/../src/vlib/main.c:1016
vm=0x7f57af8e2400 <vlib_global_main>, is_main=1)
at /home/sluong/vpp-master/vpp/build-data/../src/vlib/main.c:1500
I am able to reproduce the problem consistently with the below procedure.
1. Create 3 memif interfaces between slave and master instances.
2. Type 'quit' on the slave. Neither crashes the first time.
3. Bring back the slave. Type 'quit' on the master. Neither crashes.
4. Bring back the master. Type 'quit' on the slave. The master crashes.
There are two places the interrupt line is disconnected and the unix file is
removed via the call unix_file_del ()
1. memif_int_fd_read_ready ()
2. memif_disconnect () which is called via multiple places in memif.
When the crash happens, the unix file was removed from memif_disconnect ()
via memif_conn_fd_read_ready () with size of the message == 0 in recvmsg ().
It is noted when the unix file was removed from memif_int_fd_read_ready (),
it never crashes. It is a race condition. However, if I follow the
aformentioned procedure, the crash always happens.
The reason the crash happens when memif_disconnect () removes the unix file
is because there may still be pending input in linux_epoll_input (). When
linux_epoll_input () tries to access the unix file via the line 200
unix_file_t *f = pool_elt_at_index (um->file_pool, i);
it crashes.
We could add code in linux_epoll_input () to avoid the crash if the index
for the particular file_pool is already free. Or we could fix memif to not
remove the unix file in memif_conn_fd_read_ready () when recvmsg () got 0
byte and just postpone the unix file deletion in memif_int_fd_read_ready ()
later after linux_epoll_input () got a chance to run to empty the input
stream.
I choose to fix the problem in the latter approach. I split the function
memif_disconnect () into two parts. For the code path which
memif_conn_fd_read_ready () calls memif_disconnect (), it does not remove the
unix file. All other calls to memif_disconnect () will continue to do what
it uses to do to avoid regression.
Please let me know if I should fix the problem other way.
Change-Id: I8efe2a3d24c6581609bc7b6fe82c2b59c22d8e4b
Signed-off-by: Steven <sluong@cisco.com>
Vector Packet Processing
Introduction
The VPP platform is an extensible framework that provides out-of-the-box production quality switch/router functionality. It is the open source version of Cisco's Vector Packet Processing (VPP) technology: a high performance, packet-processing stack that can run on commodity CPUs.
The benefits of this implementation of VPP are its high performance, proven technology, its modularity and flexibility, and rich feature set.
For more information on VPP and its features please visit the FD.io website and What is VPP? pages.
Changes
Details of the changes leading up to this version of VPP can be found under @ref release_notes.
Directory layout
| Directory name | Description |
|---|---|
| build-data | Build metadata |
| build-root | Build output directory |
| doxygen | Documentation generator configuration |
| dpdk | DPDK patches and build infrastructure |
| @ref src | VPP source code |
| @ref src/plugins | VPP bundled plugins directory |
| @ref src/svm | Shared virtual memory allocation library |
| src/tests | Unit tests |
| src/vat | VPP API test program |
| @ref src/vlib | VPP application library |
| @ref src/vlibapi | VPP API library |
| @ref src/vlibmemory | VPP Memory management |
| @ref src/vlibsocket | VPP Socket I/O |
| @ref src/vnet | VPP networking |
| @ref src/vpp | VPP application |
| @ref src/vpp-api | VPP application API bindings |
| @ref src/vppinfra | VPP core library |
| test | Unit tests |
| @ref src/vpp/api | Not-yet-relocated API bindings |
Getting started
In general anyone interested in building, developing or running VPP should consult the VPP wiki for more complete documentation.
In particular, readers are recommended to take a look at [Pulling, Building, Running, Hacking, Pushing](https://wiki.fd.io/view/VPP/Pulling,_Building,_Run ning,_Hacking_and_Pushing_VPP_Code) which provides extensive step-by-step coverage of the topic.
For the impatient, some salient information is distilled below.
Quick-start: On an existing Linux host
To install system dependencies, build VPP and then install it, simply run the
build script. This should be performed a non-privileged user with sudo
access from the project base directory:
./extras/vagrant/build.sh
If you want a more fine-grained approach because you intend to do some
development work, the Makefile in the root directory of the source tree
provides several convenience shortcuts as make targets that may be of
interest. To see the available targets run:
make
Quick-start: Vagrant
The directory extras/vagrant contains a VagrantFile and supporting
scripts to bootstrap a working VPP inside a Vagrant-managed Virtual Machine.
This VM can then be used to test concepts with VPP or as a development
platform to extend VPP. Some obvious caveats apply when using a VM for VPP
since its performance will never match that of bare metal; if your work is
timing or performance sensitive, consider using bare metal in addition or
instead of the VM.
For this to work you will need a working installation of Vagrant. Instructions for this can be found [on the Setting up Vagrant wiki page] (https://wiki.fd.io/view/DEV/Setting_Up_Vagrant).
More information
Several modules provide documentation, see @subpage user_doc for more information.
Visit the VPP wiki for details on more advanced building strategies and development notes.
Test Framework
There is PyDoc generated documentation available for the VPP test framework. See @subpage test_framework_doc for details.