On Mon, 14 Jun 2021 15:28:01 GMT, Mark Sheppard <mshep...@openjdk.org> wrote:
> JDK-8265369 [macos-aarch64] java/net/MulticastSocket/Promiscuous.java failed
> with "SocketException: Cannot allocate memory"
>
> The test java/net/MulticastSocket/Promiscuous.java has been observed to fail
> on a regular basis on macosx-aarch.
> This is typically under heavy test load on a test machine. Analysis of the
> problem have
> shown that the setsockopt for joining a multicast group will intermittently
> fail with ENOMEM.
>
> While analysis of test environment shows significant memory usage and some
> memory pressure, it is
> not excessive and as such it is deemed transition or temporary condition,
> such that a retry of the
> setsockopt system call, has been seen to mitigate the issue. This adds to the
> stability of the
> Promiscuous.java test and reduces test failure noise.
>
> The proposed fix is in
> open/src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c
> in the mcast_join_leave function. That is, if setsockopt to join an mcast
> group fails, and the errno == ENOMEM,
> then re-invoke the setsockopt system call for joining a mcast group.
> The change has been applied as a conditional compilation.
> Additionally this change result in the Promiscuous.java test being removed
> from the
> ProblemList.txt.
>
> Please oblige and review the changes for a fix of the issue JDK-8265369
src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c line 2017:
> 2015: }
> 2016: } else {
> 2017: #endif
The handling of ENOMEM here is consistent with how it is handled in the NIO
area - good.
I wonder if a little restructuring may simplify the call flow? For example,
something similar to:
int n;
...
/*
* Join the multicast group.
*/
n = setsockopt(fd, IPPROTO_IP, (join ? IP_ADD_MEMBERSHIP:IP_DROP_MEMBERSHIP),
(char *) &mname, mname_len);
#ifdef __APPLE__
// workaround macOS bug where IP_ADD/DROP_MEMBERSHIP fails intermittently
if (n < 0 && errno == ENOMEM) {
n = setsockopt(fd, IPPROTO_IP, (join ?
IP_ADD_MEMBERSHIP:IP_DROP_MEMBERSHIP),
(char *) &mname, mname_len);
}
#endif
if (n < 0) { ...
-------------
PR: https://git.openjdk.java.net/jdk17/pull/44
