On Tue, 29 Sep 2026 10:36:58 +0200 Sebastien Bacher <[email protected]> wrote: > Package: dhcpcd-base > Version: 1:10.5.2-5 > Severity: important > Tags: upstream patch > Forwarded: https://github.com/NetworkConfiguration/dhcpcd/issues/716 > > Dear Maintainer, > > dhcpcd 10.5.2 no longer points stdout/stderr at /dev/null when it > daemonises. Any caller that reads dhcpcd's output through a pipe > therefore hangs forever, even though the lease is applied. 10.3.2 is > not affected. > > Reproducer: > > dhcpcd --ipv4only --waitip --persistent --noarp eth0 | cat > > With 10.5.2 this never returns, and /proc/<pid>/fd/{1,2} of the daemon > still point to the pipe. > > Cause: upstream commit 62018896 made setrlimit(RLIMIT_NOFILE, {0,0}) in > ps_dropprivs() unconditional. On Linux, dup2() onto fds 1/2 then fails > with EBADF, and dhcpcd_daemonised() ignores the error. > > Known affected callers: > - cloud-init ephemeral DHCP: waits until its 300s timeout, slowing > boot (upstream #737) > - netplan.io autopkgtest "wifi" (subprocess.check_output on > dhcpcd -w), which now hangs until the timeout in Ubuntu: > https://autopkgtest.ubuntu.com/packages/n/netplan.io/stonking/amd64 > - sysvinit setups where rc scripts wait on the console (upstream #716) > > Upstream fix (open PR, not merged yet): > https://github.com/NetworkConfiguration/dhcpcd/pull/733 > > Please consider applying it as a patch until the next upstream release.
Thanks. Please note that someone else at Canonical also submitted a MR for an NMU on Salsa for this one. This is overkill. An NMU is not welcome on an actively maintained package. Martin-Éric
