On Mon, May 12, 2025 at 02:23:12PM +0200, Michal Luczaj wrote:
On 5/7/25 10:26, Stefano Garzarella wrote:
On Wed, 7 May 2025 at 00:47, Michal Luczaj <m...@rbox.co> wrote:
On 5/6/25 11:46, Stefano Garzarella wrote:
On Tue, 6 May 2025 at 11:43, Stefano Garzarella <sgarz...@redhat.com> wrote:
On Thu, May 01, 2025 at 10:05:24AM +0200, Michal Luczaj wrote:
There was an issue with SO_LINGER: instead of blocking until all queued
messages for the socket have been successfully sent (or the linger timeout
has been reached), close() would block until packets were handled by the
peer.
This is a new behaviour that only new kernels will follow, so I think
it is better to add a new test instead of extending a pre-existing test
that we described as "SOCK_STREAM SO_LINGER null-ptr-deref".
The old test should continue to check the null-ptr-deref also for old
kernels, while the new test will check the new behaviour, so we can skip
the new test while testing an old kernel.
Right, I'll split it.
I also saw that we don't have any test to verify that actually the
lingering is working, should we add it since we are touching it?
Yeah, I agree we should. Do you have any suggestion how this could be done
reliably?
Can we play with SO_VM_SOCKETS_BUFFER_SIZE like in credit-update tests?
One peer can set it (e.g. to 1k), accept the connection, but without
read anything. The other peer can set the linger timeout, send more
bytes than the buffer size set by the receiver.
At this point the extra bytes should stay on the sender socket buffer,
so we can do the close() and it should time out, and we can check if
it happens.
WDYT?
Haven't we discussed this approach in [1]? I've reported that I can't make
Sorry, I forgot. What was the conclusion? Why this can't work?
it work. But maybe I'm misunderstanding something, please see the code
below.
What I should check in the code below?
Thanks,
Stefano
[1]:
https://lore.kernel.org/netdev/df2d51fd-03e7-477f-8aea-938446f47...@rbox.co/
import termios, time
from socket import *
SIOCOUTQ = termios.TIOCOUTQ
VMADDR_CID_LOCAL = 1
SZ = 1024
def set_linger(s, timeout):
optval = (timeout << 32) | 1
s.setsockopt(SOL_SOCKET, SO_LINGER, optval)
assert s.getsockopt(SOL_SOCKET, SO_LINGER) == optval
def set_bufsz(s, size):
s.setsockopt(AF_VSOCK, SO_VM_SOCKETS_BUFFER_SIZE, size)
assert s.getsockopt(AF_VSOCK, SO_VM_SOCKETS_BUFFER_SIZE) == size
def check_lingering(addr):
lis = socket(AF_VSOCK, SOCK_STREAM)
lis.bind(addr)
lis.listen()
set_bufsz(lis, SZ)
s = socket(AF_VSOCK, SOCK_STREAM)
set_linger(s, 5)
s.connect(lis.getsockname())
p, _ = lis.accept()
s.send(b'x')
p.recv(1)
print("sending...")
s.send(b'x' * (SZ+1)) # blocks
print("sent")
print("closing...")
ts = time.time()
s.close()
print("done in %ds" % (time.time() - ts))
check_lingering((VMADDR_CID_LOCAL, 1234))
