Package: ppp
Version: 2.5.3-1+0local1
Severity: normal
Dear Maintainer,
please update ppp to version 2.5.3
*** Reporter, please consider answering these questions, where appropriate ***
* What led up to the situation?
/etc/ppp/peers/tng had defaultroute6. Before installing the IPv6 default
route, pppd's defaultroute6_exists() reads /proc/net/ipv6_route line-by-line -
a seq_file where every 4 KB read re-walks the kernel FIB trie across all
tables. Since ~May 22, bird carries a full BGP IPv6 table (~249k routes, kernel
table 100). After each reconnect, bird re-converges and re-inserts routes at
the same time pppd scans - a mutual livelock (verified live: pppd spinning in
userspace state=R/empty kernel stack, bird at 52 % CPU with maxed 212 KB
netlink Recv-Q, table growing ~120 routes/s). The scan took up to 15 minutes;
pppd couldn't answer the BRAS's LCP echoes meanwhile, so the BRAS killed the
session, and the cycle repeated - each round shorter as the table shrank -
until one attempt completed in time. That's why reestablishment "took a long
time" since May 23.
* What exactly did you do (or not do) that was effective (or
ineffective)?
Workaround:
1. Removed defaultroute6 from /etc/ppp/peers/tng (backup: tng.bak-20260604)
2. Added /etc/ppp/ipv6-up.d/00defaultroute: ip -6 route replace default dev
"$IFACE" metric 1024 - pure netlink, instant at any table size, produces the
identical route, auto-removed when ppp0 drops
3. Restarted pppd (it only reads the peers file at startup) - reconnect now
completes in ~3 seconds, ConfAck→LL-address in the same second, bird
unaffected, default route present
Fix: Update to version 2.5.3
*** End of the template - remove these template lines ***
-- System Information:
Debian Release: 13.5
APT prefers stable-security
APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 6.12.90+deb13.1-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=C, LC_CTYPE=C.utf8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages ppp depends on:
ii libc6 2.41-12+deb13u3
ii libcrypt1 1:4.4.38-1
ii libpam-modules 1.7.0-5
ii libpam-runtime 1.7.0-5
ii libpam0g 1.7.0-5
ii libpcap0.8t64 1.10.5-2
ii libssl3t64 3.5.6-1~deb13u1
ii libsystemd0 257.13-1~deb13u1
ii procps 2:4.0.4-9
ppp recommends no packages.
ppp suggests no packages.
-- Configuration Files:
-- no debconf information
