On Wed, Oct 15, 2025 at 08:47:21PM +0000, Gleb Smirnoff wrote:
> The branch main has been updated by glebius:
>
> URL:
> https://cgit.FreeBSD.org/src/commit/?id=4548b9f3a8167a340a5086ed51a76d932c9ab3cc
>
> commit 4548b9f3a8167a340a5086ed51a76d932c9ab3cc
> Author: Gleb Smirnoff <[email protected]>
> AuthorDate: 2025-10-15 20:01:25 +0000
> Commit: Gleb Smirnoff <[email protected]>
> CommitDate: 2025-10-15 20:47:11 +0000
>
> unix/stream: plug a corner case when control externalization failed
>
> while peer has closed its end.
>
> Reported by: [email protected]
Shouldn't this be MFCed?
Could you please be sure to add Fixes tags to such commits? It becomes
much easier to find missing MFCs with that metadata available. A few of
us have discussed using git notes to encode such info after the fact,
but this is not available yet.
> ---
> sys/kern/uipc_usrreq.c | 20 ++++++++++++--------
> 1 file changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/sys/kern/uipc_usrreq.c b/sys/kern/uipc_usrreq.c
> index c5fc1e84ce3f..90489e99491a 100644
> --- a/sys/kern/uipc_usrreq.c
> +++ b/sys/kern/uipc_usrreq.c
> @@ -1559,15 +1559,19 @@ restart:
> mc_init_m(&cmc, control);
>
> SOCK_RECVBUF_LOCK(so);
> - MPASS(!(sb->sb_state & SBS_CANTRCVMORE));
> -
> - if (__predict_false(cmc.mc_len + sb->sb_ccc +
> - sb->sb_ctl > sb->sb_hiwat)) {
> + if (__predict_false(
> + (sb->sb_state & SBS_CANTRCVMORE) ||
> + cmc.mc_len + sb->sb_ccc + sb->sb_ctl >
> + sb->sb_hiwat)) {
> /*
> - * Too bad, while unp_externalize() was
> - * failing, the other side had filled
> - * the buffer and we can't prepend data
> - * back. Losing data!
> + * While the lock was dropped and we
> + * were failing in unp_externalize(),
> + * the peer could has a) disconnected,
> + * b) filled the buffer so that we
> + * can't prepend data back.
> + * These are two edge conditions that
> + * we just can't handle, so lose the
> + * data and return the error.
> */
> SOCK_RECVBUF_UNLOCK(so);
> SOCK_IO_RECV_UNLOCK(so);
