Re: [PATCH] flow: Set EPOLLFD_ID_DEFAULT on newly allocated flows, not EPOLLFD_ID_INVALID

On Mon, 8 Dec 2025 22:28:22 +0100 Stefano Brivio wrote:

We're somehow hitting:

ASSERTION FAILED in flow_epollfd (flow.c:362): f->epollid < ((1 << 8) - 1)

on an inbound spliced connection, with a single forwarded port, an HTTP server in a Podman container, and a GET request. Reproducer at https://bodhi.fedoraproject.org/updates/FEDORA-2025-93b4eb64c3#comment-44734...

printf 'FROM registry.fedoraproject.org/fedora:latest\nRUN /usr/bin/dnf install -y httpd\nEXPOSE 80\nCMD ["-D", "FOREGROUND"]\nENTRYPOINT ["/usr/sbin/httpd"]\n' > Containerfile podman build -t fedora-httpd $(pwd) podman run -d -p 8080:80 localhost/fedora-httpd

curl http://localhost:8080

I guess we don't set EPOLLFD_ID_DEFAULT early enough on inbound spliced sockets for some reason and we get a socket event while we still have EPOLLFD_ID_INVALID set.

As we're not really using epoll identifiers yet, set EPOLLFD_ID_DEFAULT right away on newly allocated flows, while we figure this out.

Link: https://bodhi.fedoraproject.org/updates/FEDORA-2025-93b4eb64c3#comment-44734... Signed-off-by: Stefano Brivio --- I just merged this, posting for awareness / review.

Ah, never mind, this makes it worse somehow: 5.6384: Flow 0 (TCP connection (spliced)): SPLICE_CONNECT 5.6384: Flow 0 (TCP connection (spliced)): ERROR on epoll_ctl(): No such file or directory ...still looking for a workaround / fix. -- Stefano