Change Details

There is at least one consumer (netgraph) which calls pr_sockaddr and pr_peeraddr from within epoch, which immediately panics with invariants due to malloc(..., M_WAITOK) performed there. I think a second set of ops should be added which accepts passing a preallocated buffer, even something on-stack. struct sockaddr has a small upper bound size, so this is very feasible. Illustrative patch below. If #network is ok with it, I'll make it operational. Note that callers only need to allocate ``` __offsetof(struct sockaddr, sa_data) + SOCK_MAXADDRLEN ``` bytes. This can be hidden away in struct sockaddr_max or perhaps just a macro indicating the size. Alternatively a set of routines which take malloc flags can be added, but imo this only adds a failure point (malloc returning NULL) which does not have to exist. Comments?

At least netgraph calls pr_sockaddr and pr_peeraddr from within epoch (see ng_ksocket_rcvmsg -> NGM_KSOCKET_GETPEERNAME), which immediately panics with invariants due to malloc(..., M_WAITOK) performed there. I think a second set of ops should be added which accepts passing a preallocated buffer, even something on-stack. struct sockaddr has a small upper bound size, so this is very feasible. Illustrative patch below. If #network is ok with it, I'll make it operational. Note that callers only need to allocate ``` __offsetof(struct sockaddr, sa_data) + SOCK_MAXADDRLEN ``` bytes. This can be hidden away in struct sockaddr_max or perhaps just a macro indicating the size. Alternatively a set of routines which take malloc flags can be added, but imo this only adds a failure point (malloc returning NULL) which does not have to exist. Comments?

There is aAt least one consumer (netgraph) whichh calls pr_sockaddr and pr_peeraddr from within epoch (see ng_ksocket_rcvmsg -> NGM_KSOCKET_GETPEERNAME), which immediately panics with invariants due to malloc(..., M_WAITOK) performed there. I think a second set of ops should be added which accepts passing a preallocated buffer, even something on-stack. struct sockaddr has a small upper bound size, so this is very feasible. Illustrative patch below. If #network is ok with it, I'll make it operational. Note that callers only need to allocate ``` __offsetof(struct sockaddr, sa_data) + SOCK_MAXADDRLEN ``` bytes. This can be hidden away in struct sockaddr_max or perhaps just a macro indicating the size. Alternatively a set of routines which take malloc flags can be added, but imo this only adds a failure point (malloc returning NULL) which does not have to exist. Comments?